Complete Organisms and Populations Question Bank & Solutions (110 Questions)
Q1 of 110
NEET NCERT Line-by-Line
Ecology is concerned with how many levels of biological organisation?
(A)
Four
(B)
Six
(C)
Two
(D)
Three
Show Answer & NCERT Explanation
Correct Answer: (A) Four
Four — organisms, populations, communities and biomes.
Q2 of 110
NEET NCERT Line-by-Line
Which of the following is NOT one of the four levels of biological organisation that ecology is concerned with (as per NCERT)?
(A)
Organisms
(B)
Populations
(C)
Communities
(D)
Ecosystems
Show Answer & NCERT Explanation
Correct Answer: (D) Ecosystems
NCERT explicitly lists organisms, populations, communities and biomes. 'Ecosystem' is the classic distractor.
Q3 of 110
NEET NCERT Line-by-Line
Who is revered as the Father of Ecology in India?
(A)
Ramdeo Misra
(B)
Robert MacArthur
(C)
Charles Elton
(D)
G. F. Gause
Show Answer & NCERT Explanation
Correct Answer: (A) Ramdeo Misra
Ramdeo Misra (1908–1998), who established ecology at BHU, Varanasi.
Q4 of 110
NEET NCERT Line-by-Line
Ramdeo Misra obtained his PhD in Ecology (1937) under which professor?
(A)
Prof. J. H. Connell
(B)
Prof. R. H. MacArthur
(C)
Prof. P. F. Verhulst
(D)
Prof. W. H. Pearsall
Show Answer & NCERT Explanation
Correct Answer: (D) Prof. W. H. Pearsall
Under Prof. W. H. Pearsall, FRS, at Leeds University, UK.
Q5 of 110
NEET NCERT Line-by-Line
The National Committee for Environmental Planning and Coordination was established in which year, due to Ramdeo Misra's efforts?
(A)
1962
(B)
1972
(C)
1984
(D)
1998
Show Answer & NCERT Explanation
Correct Answer: (B) 1972
1972. It later paved the way for the Ministry of Environment and Forests (1984).
Q6 of 110
NEET NCERT Line-by-Line
'Why does the bird sing?' is an example of a question that seeks the:
(A)
Significance of the process
(B)
Anatomy of the voice box
(C)
Rate of the process
(D)
Mechanism behind the process
Show Answer & NCERT Explanation
Correct Answer: (A) Significance of the process
'Why-type' questions seek significance. 'How-type' questions seek the mechanism.
Q7 of 110
NEET NCERT Line-by-Line
Natural selection operates to evolve desired traits at the level of the:
(A)
Community
(B)
Biome
(C)
Individual
(D)
Population
Show Answer & NCERT Explanation
Correct Answer: (D) Population
The individual copes with the changed environment, but natural selection operates at the population level.
Q8 of 110
NEET NCERT Line-by-Line
Population ecology is important because it links ecology to:
(A)
Population genetics and evolution
(B)
Taxonomy and systematics
(C)
Biotechnology and genomics
(D)
Biochemistry and physiology
Show Answer & NCERT Explanation
Correct Answer: (A) Population genetics and evolution
Population ecology links ecology to population genetics and evolution.
Q9 of 110
NEET NCERT Line-by-Line
Which of the following is NOT an attribute of a population?
(A)
Age distribution
(B)
Birth rate
(C)
Sex ratio
(D)
Birth
Show Answer & NCERT Explanation
Correct Answer: (D) Birth
An individual has births and deaths; a population has birth RATES and death RATES.
Q10 of 110
NEET NCERT Line-by-Line
A group of individuals resulting from asexual reproduction is:
(A)
Still generally considered a population for ecological studies
(B)
Called a community
(C)
Never called a population
(D)
Called a clone, not a population
Show Answer & NCERT Explanation
Correct Answer: (A) Still generally considered a population for ecological studies
NCERT: even asexually produced groups are generally considered a population for ecological studies.
Q11 of 110
NEET NCERT Line-by-Line
In a pond there were 20 lotus plants last year; 8 new plants were added by reproduction. The birth rate is:
(A)
2.5 offspring per lotus per year
(B)
0.286 offspring per lotus per year
(C)
0.4 offspring per lotus per year
(D)
0.8 offspring per lotus per year
Show Answer & NCERT Explanation
Correct Answer: (C) 0.4 offspring per lotus per year
8/20 = 0.4. Divide by the ORIGINAL 20, not the new total of 28.
Q12 of 110
NEET NCERT Line-by-Line
4 individuals of a laboratory population of 40 fruitflies died in a week. The death rate is:
(A)
0.4 per fruitfly per week
(B)
10 per fruitfly per week
(C)
0.01 per fruitfly per week
(D)
0.1 per fruitfly per week
Show Answer & NCERT Explanation
Correct Answer: (D) 0.1 per fruitfly per week
4/40 = 0.1 individuals per fruitfly per week.
Q13 of 110
NEET NCERT Line-by-Line
Which of these is a valid example of a population?
(A)
All the cormorants in a wetland
(B)
All the microbes and fungi in the soil
(C)
All the herbivores in a grassland
(D)
All the plants and animals in a pond
Show Answer & NCERT Explanation
Correct Answer: (A) All the cormorants in a wetland
A population = individuals of a single species. Cormorants in a wetland qualifies; the others mix species.
Q14 of 110
NEET NCERT Line-by-Line
An age pyramid with a broad base and tapering top represents a population that is:
(A)
Declining
(B)
Stable
(C)
Growing (expanding)
(D)
Extinct
Show Answer & NCERT Explanation
Correct Answer: (C) Growing (expanding)
Broad base = many young = growing/expanding.
Q15 of 110
NEET NCERT Line-by-Line
A bell-shaped age pyramid indicates a:
(A)
Declining population
(B)
Randomly fluctuating population
(C)
Growing population
(D)
Stable population
Show Answer & NCERT Explanation
Correct Answer: (D) Stable population
Bell-shaped = stable. Narrow base = declining. Triangle = growing.
Q16 of 110
NEET NCERT Line-by-Line
Population density is technically designated by the symbol:
Show Answer & NCERT Explanation
Correct Answer: (A) N
N = population density. K = carrying capacity; r = intrinsic rate of natural increase.
Q17 of 110
NEET NCERT Line-by-Line
In an area with 200 carrot grass plants and one huge banyan tree, the best measure of the banyan's population density is:
(A)
Total number
(B)
Per cent cover or biomass
(C)
Relative density
(D)
Sex ratio
Show Answer & NCERT Explanation
Correct Answer: (B) Per cent cover or biomass
Total number would underestimate the enormous role of the banyan. Use per cent cover or biomass.
Q18 of 110
NEET NCERT Line-by-Line
Parthenium hysterophorus is the scientific name of:
(A)
Cuscuta
(B)
Prickly pear
(C)
Carrot grass
(D)
Bamboo
Show Answer & NCERT Explanation
Correct Answer: (C) Carrot grass
Carrot grass — used in NCERT's banyan-vs-carrot-grass density example.
Q19 of 110
NEET NCERT Line-by-Line
The tiger census in Indian national parks is often based on:
(A)
Radio collars only
(B)
Camera counts of every individual
(C)
Aerial photography
(D)
Pug marks and faecal pellets
Show Answer & NCERT Explanation
Correct Answer: (D) Pug marks and faecal pellets
Indirect estimation via pug marks and faecal pellets.
Q20 of 110
NEET NCERT Line-by-Line
'Number of fish caught per trap' in a lake is a measure of:
(A)
Relative density
(B)
Biomass
(C)
Carrying capacity
(D)
Absolute density
Show Answer & NCERT Explanation
Correct Answer: (A) Relative density
Relative density — good enough when absolute density is not needed.
Q21 of 110
NEET NCERT Line-by-Line
Which population may fall below 10 individuals at Bharatpur wetlands in a given year?
(A)
Chlamydomonas
(B)
Siberian crane
(C)
Cormorant
(D)
Flamingo
Show Answer & NCERT Explanation
Correct Answer: (B) Siberian crane
Siberian cranes — NCERT's example of an extremely small population.
Q22 of 110
NEET NCERT Line-by-Line
Which population in a pond may run into millions?
(A)
Lotus
(B)
Cormorant
(C)
Chlamydomonas
(D)
Teakwood
Show Answer & NCERT Explanation
Correct Answer: (C) Chlamydomonas
Chlamydomonas — NCERT's example of an extremely large population.
Q23 of 110
NEET NCERT Line-by-Line
Which pair of processes INCREASES population density?
(A)
Mortality and emigration
(B)
Natality and emigration
(C)
Mortality and immigration
(D)
Natality and immigration
Show Answer & NCERT Explanation
Correct Answer: (D) Natality and immigration
Natality + Immigration increase density. Mortality + Emigration decrease it. Mnemonic: 'NI up, ME down'.
Q24 of 110
NEET NCERT Line-by-Line
The correct expression for population density at time t+1 is:
(A)
Nt+1 = Nt + [(B + I) − (D + E)]
(B)
Nt+1 = Nt − [(B + I) − (D + E)]
(C)
Nt+1 = Nt × [(B + I) / (D + E)]
(D)
Nt+1 = Nt + [(B + E) − (D + I)]
Show Answer & NCERT Explanation
Correct Answer: (A) Nt+1 = Nt + [(B + I) − (D + E)]
Nt+1 = Nt + [(B + I) − (D + E)].
Q25 of 110
NEET NCERT Line-by-Line
Immigration refers to:
(A)
Individuals of any species entering the habitat
(B)
Individuals of the same species that have come into the habitat from elsewhere
(C)
Individuals leaving the habitat
(D)
Births added to the initial density
Show Answer & NCERT Explanation
Correct Answer: (B) Individuals of the same species that have come into the habitat from elsewhere
Crucially, immigration involves individuals of the SAME species.
Q26 of 110
NEET NCERT Line-by-Line
Under normal conditions, which factors most influence population density?
(A)
Sex ratio and age distribution
(B)
Immigration and emigration
(C)
Births and deaths
(D)
Predation and weather only
Show Answer & NCERT Explanation
Correct Answer: (C) Births and deaths
Births and deaths dominate; I and E matter only under special conditions.
Q27 of 110
NEET NCERT Line-by-Line
In which situation may immigration contribute MORE to population growth than birth rate?
(A)
During a severe drought
(B)
When the population is at carrying capacity
(C)
In a stable climax forest
(D)
When a new habitat is just being colonised
Show Answer & NCERT Explanation
Correct Answer: (D) When a new habitat is just being colonised
NCERT: 'if a new habitat is just being colonised, immigration may contribute more significantly to population growth than birth rates.'
Q28 of 110
NEET NCERT Line-by-Line
Exponential growth of a population produces a curve that is:
(A)
J-shaped
(B)
U-shaped
(C)
Bell-shaped
(D)
S-shaped
Show Answer & NCERT Explanation
Correct Answer: (A) J-shaped
Exponential (geometric) growth = J-shaped curve.
Q29 of 110
NEET NCERT Line-by-Line
In the equation dN/dt = rN, 'r' is called the:
(A)
Rate of reproduction
(B)
Intrinsic rate of natural increase
(C)
Carrying capacity
(D)
Recruitment index
Show Answer & NCERT Explanation
Correct Answer: (B) Intrinsic rate of natural increase
r = intrinsic rate of natural increase = b − d.
Q30 of 110
NEET NCERT Line-by-Line
The integral form of the exponential growth equation is:
(A)
Nt = N0 r^t
(B)
Nt = rN[(K−N)/K]
(C)
Nt = N0 e^(rt)
(D)
Nt = N0 + rt
Show Answer & NCERT Explanation
Correct Answer: (C) Nt = N0 e^(rt)
Nt = N0 e^(rt) where e = 2.71828.
Q31 of 110
NEET NCERT Line-by-Line
The value of 'e', the base of natural logarithms, is:
(A)
3.14159
(B)
2.71828
(C)
1.61803
(D)
0.69315
Show Answer & NCERT Explanation
Correct Answer: (B) 2.71828
e = 2.71828.
Q32 of 110
NEET NCERT Line-by-Line
The r value for the Norway rat is:
(A)
0.12
(B)
0.0205
(C)
0.015
(D)
0.693
Show Answer & NCERT Explanation
Correct Answer: (C) 0.015
Norway rat r = 0.015.
Q33 of 110
NEET NCERT Line-by-Line
The r value for the flour beetle is:
(A)
0.015
(B)
0.0205
(C)
0.12
(D)
0.21
Show Answer & NCERT Explanation
Correct Answer: (C) 0.12
Flour beetle r = 0.12 — the highest of NCERT's three examples.
Q34 of 110
NEET NCERT Line-by-Line
In 1981, the r value for the human population in India was:
(A)
0.015
(B)
0.0205
(C)
0.12
(D)
0.205
Show Answer & NCERT Explanation
Correct Answer: (B) 0.0205
0.0205.
Q35 of 110
NEET NCERT Line-by-Line
Which of these has the HIGHEST r value?
(A)
Norway rat
(B)
Flour beetle
(C)
Human population of India (1981)
(D)
All are equal
Show Answer & NCERT Explanation
Correct Answer: (B) Flour beetle
Flour beetle (0.12) > India 1981 (0.0205) > Norway rat (0.015). Mnemonic: R-I-B goes up.
Q36 of 110
NEET NCERT Line-by-Line
The chessboard-and-wheat-grains anecdote is used to illustrate:
(A)
Carrying capacity
(B)
Resource partitioning
(C)
Logistic growth
(D)
Exponential growth
Show Answer & NCERT Explanation
Correct Answer: (D) Exponential growth
Doubling across 64 squares demonstrates the explosive nature of exponential growth.
Q37 of 110
NEET NCERT Line-by-Line
Which organism does NCERT use, doubling daily by binary fission for 64 days, to illustrate exponential growth?
(A)
Paramecium
(B)
Amoeba
(C)
Escherichia coli
(D)
Chlamydomonas
Show Answer & NCERT Explanation
Correct Answer: (A) Paramecium
Paramecium, doubling in numbers every day given unlimited food and space.
Q38 of 110
NEET NCERT Line-by-Line
Darwin used which slow-growing animal to show enormous population build-up in the absence of checks?
(A)
Whale
(B)
Elephant
(C)
Tortoise
(D)
Rhinoceros
Show Answer & NCERT Explanation
Correct Answer: (B) Elephant
The elephant.
Q39 of 110
NEET NCERT Line-by-Line
Nature's carrying capacity is denoted by:
Show Answer & NCERT Explanation
Correct Answer: (C) K
K = the maximum number a habitat can support, beyond which no further growth is possible.
Q40 of 110
NEET NCERT Line-by-Line
The logistic growth equation is:
(A)
dN/dt = rN[(N − K)/K]
(B)
dN/dt = rK[(K − N)/N]
(C)
dN/dt = rN
(D)
dN/dt = rN[(K − N)/K]
Show Answer & NCERT Explanation
Correct Answer: (D) dN/dt = rN[(K − N)/K]
dN/dt = rN[(K − N)/K] — the Verhulst–Pearl logistic equation.
Q41 of 110
NEET NCERT Line-by-Line
Logistic growth is also known as:
(A)
Verhulst–Pearl growth
(B)
Malthusian growth
(C)
MacArthur growth
(D)
Gaussian growth
Show Answer & NCERT Explanation
Correct Answer: (A) Verhulst–Pearl growth
Verhulst–Pearl Logistic Growth.
Q42 of 110
NEET NCERT Line-by-Line
The correct sequence of phases in logistic growth is:
(A)
Lag → Deceleration → Acceleration → Asymptote
(B)
Lag → Acceleration → Deceleration → Asymptote
(C)
Asymptote → Lag → Acceleration → Deceleration
(D)
Acceleration → Lag → Deceleration → Asymptote
Show Answer & NCERT Explanation
Correct Answer: (B) Lag → Acceleration → Deceleration → Asymptote
Lag → Acceleration → Deceleration → Asymptote. Mnemonic: LADA.
Q43 of 110
NEET NCERT Line-by-Line
In the logistic equation, when N = K, the value of dN/dt is:
(A)
Equal to rN
(B)
Maximum
(C)
Zero
(D)
Negative
Show Answer & NCERT Explanation
Correct Answer: (C) Zero
(K − N)/K becomes 0, so dN/dt = 0 — the asymptote.
Q44 of 110
NEET NCERT Line-by-Line
In the logistic model, population growth rate is maximum when:
(A)
N = 2K
(B)
N = K
(C)
N = 0
(D)
N = K/2
Show Answer & NCERT Explanation
Correct Answer: (D) N = K/2
The inflection point of the S-curve is at N = K/2.
Q45 of 110
NEET NCERT Line-by-Line
When N is very small compared to K, the logistic growth curve approximates:
(A)
Exponential growth
(B)
Declining growth
(C)
Oscillatory growth
(D)
Zero growth
Show Answer & NCERT Explanation
Correct Answer: (A) Exponential growth
(K − N)/K ≈ 1, so dN/dt ≈ rN — essentially exponential.
Q46 of 110
NEET NCERT Line-by-Line
Which growth model is considered MORE REALISTIC for most animal populations, and why?
(A)
Exponential, because resources are always unlimited
(B)
Logistic, because resources are finite and become limiting
(C)
Exponential, because it is mathematically simpler
(D)
Neither; populations do not follow models
Show Answer & NCERT Explanation
Correct Answer: (B) Logistic, because resources are finite and become limiting
Resources for most animal populations are finite and become limiting sooner or later, so the logistic model is more realistic.
Q47 of 110
NEET NCERT Line-by-Line
Reproductive fitness is also called:
(A)
Gaussian fitness
(B)
Darwinian fitness
(C)
Ecological fitness
(D)
Malthusian fitness
Show Answer & NCERT Explanation
Correct Answer: (B) Darwinian fitness
Darwinian fitness — corresponding to a high r value.
Q48 of 110
NEET NCERT Line-by-Line
Which of the following breeds only ONCE in its lifetime?
(A)
Most birds
(B)
Most mammals
(C)
Pacific salmon fish
(D)
Norway rat
Show Answer & NCERT Explanation
Correct Answer: (C) Pacific salmon fish
Pacific salmon fish and bamboo breed only once. Most birds and mammals breed many times.
Q49 of 110
NEET NCERT Line-by-Line
Which produces a LARGE number of SMALL-sized offspring?
(A)
Elephants
(B)
Birds
(C)
Mammals
(D)
Oysters
Show Answer & NCERT Explanation
Correct Answer: (D) Oysters
Oysters and pelagic fishes produce many small offspring; birds and mammals produce few large ones.
Q50 of 110
NEET NCERT Line-by-Line
Life-history traits of organisms have evolved in relation to constraints imposed by:
(A)
Only abiotic components of the habitat
(B)
Only biotic components of the habitat
(C)
Both abiotic and biotic components of the habitat
(D)
Neither; they are random
Show Answer & NCERT Explanation
Correct Answer: (C) Both abiotic and biotic components of the habitat
NCERT: constraints imposed by the abiotic AND biotic components of the habitat.
Q51 of 110
NEET NCERT Line-by-Line
The interaction denoted by (+ , +) is:
(A)
Mutualism
(B)
Predation
(C)
Amensalism
(D)
Commensalism
Show Answer & NCERT Explanation
Correct Answer: (A) Mutualism
Mutualism — both species benefit.
Q52 of 110
NEET NCERT Line-by-Line
The interaction denoted by (− , −) is:
(A)
Predation
(B)
Competition
(C)
Amensalism
(D)
Parasitism
Show Answer & NCERT Explanation
Correct Answer: (B) Competition
Competition — both species lose.
Q53 of 110
NEET NCERT Line-by-Line
The interaction denoted by (+ , 0) is:
(A)
Amensalism
(B)
Mutualism
(C)
Commensalism
(D)
Parasitism
Show Answer & NCERT Explanation
Correct Answer: (C) Commensalism
Commensalism — one benefits, the other is neither harmed nor benefited.
Q54 of 110
NEET NCERT Line-by-Line
The interaction denoted by (− , 0) is:
(A)
Competition
(B)
Predation
(C)
Commensalism
(D)
Amensalism
Show Answer & NCERT Explanation
Correct Answer: (D) Amensalism
Amensalism — one species is harmed, the other is unaffected.
Q55 of 110
NEET NCERT Line-by-Line
Which TWO interactions both have the sign pattern (+ , −)?
(A)
Predation and parasitism
(B)
Competition and amensalism
(C)
Parasitism and commensalism
(D)
Mutualism and commensalism
Show Answer & NCERT Explanation
Correct Answer: (A) Predation and parasitism
Predation and parasitism — one benefits (predator/parasite), the other is harmed (prey/host).
Q56 of 110
NEET NCERT Line-by-Line
Which three interactions share the characteristic that the interacting species LIVE CLOSELY TOGETHER?
(A)
Mutualism, competition, amensalism
(B)
Predation, parasitism, commensalism
(C)
Predation, competition, mutualism
(D)
Parasitism, amensalism, mutualism
Show Answer & NCERT Explanation
Correct Answer: (B) Predation, parasitism, commensalism
NCERT states this explicitly: predation, parasitism and commensalism.
Q57 of 110
NEET NCERT Line-by-Line
Predation can be described as nature's way of:
(A)
Increasing the carrying capacity
(B)
Reducing biodiversity
(C)
Transferring to higher trophic levels the energy fixed by plants
(D)
Preventing evolution
Show Answer & NCERT Explanation
Correct Answer: (C) Transferring to higher trophic levels the energy fixed by plants
Predators are 'conduits' for energy transfer across trophic levels.
Q58 of 110
NEET NCERT Line-by-Line
A sparrow eating a seed is ecologically:
(A)
A parasite
(B)
A commensal
(C)
A decomposer
(D)
A predator
Show Answer & NCERT Explanation
Correct Answer: (D) A predator
NCERT: 'a sparrow eating any seed is no less a predator.'
Q59 of 110
NEET NCERT Line-by-Line
Exotic species become invasive in a new area mainly because:
(A)
The invaded land does not have their natural predators
(B)
They reproduce asexually
(C)
They have lower r values
(D)
They have higher carrying capacity
Show Answer & NCERT Explanation
Correct Answer: (A) The invaded land does not have their natural predators
The absence of natural predators in the invaded land allows them to spread unchecked.
Q60 of 110
NEET NCERT Line-by-Line
The prickly pear cactus was introduced into Australia in:
(A)
The early 1820s
(B)
The early 1920s
(C)
The late 1950s
(D)
The 1970s
Show Answer & NCERT Explanation
Correct Answer: (B) The early 1920s
Early 1920s — it then spread into millions of hectares of rangeland.
Q61 of 110
NEET NCERT Line-by-Line
The prickly pear cactus in Australia was finally brought under control by introducing:
(A)
A herbicide-resistant grass
(B)
Goats
(C)
A cactus-feeding moth
(D)
A cactus-feeding beetle
Show Answer & NCERT Explanation
Correct Answer: (C) A cactus-feeding moth
A cactus-feeding predator — a MOTH — from the cactus's natural habitat.
Q62 of 110
NEET NCERT Line-by-Line
Biological control of agricultural pests is based on:
(A)
The ability of the parasite to kill the host instantly
(B)
Increasing carrying capacity
(C)
Competitive release
(D)
The ability of the predator to regulate prey population
Show Answer & NCERT Explanation
Correct Answer: (D) The ability of the predator to regulate prey population
It exploits the predator's capacity to keep prey populations under control.
Q63 of 110
NEET NCERT Line-by-Line
Pisaster is a:
(A)
Starfish predator
(B)
Parasitic wasp
(C)
Cactus-feeding moth
(D)
Barnacle
Show Answer & NCERT Explanation
Correct Answer: (A) Starfish predator
Pisaster is an important starfish predator in the rocky intertidal communities of the American Pacific Coast.
Q64 of 110
NEET NCERT Line-by-Line
When all Pisaster starfish were removed from an enclosed intertidal area, what happened?
(A)
Invertebrate diversity increased
(B)
More than 10 species of invertebrates became extinct within a year
(C)
The area became a barren rock
(D)
Nothing changed
Show Answer & NCERT Explanation
Correct Answer: (B) More than 10 species of invertebrates became extinct within a year
More than 10 invertebrate species went extinct within a year — because of interspecific competition.
Q65 of 110
NEET NCERT Line-by-Line
The extinction of invertebrates following Pisaster removal was caused by:
(A)
Pollution
(B)
Starvation
(C)
Interspecific competition
(D)
Disease
Show Answer & NCERT Explanation
Correct Answer: (C) Interspecific competition
With the predator gone, superior competitors eliminated the rest — interspecific competition.
Q66 of 110
NEET NCERT Line-by-Line
Predators help maintain species diversity in a community by:
(A)
Eliminating all prey species equally
(B)
Raising the carrying capacity
(C)
Increasing the birth rate of prey
(D)
Reducing the intensity of competition among competing prey species
Show Answer & NCERT Explanation
Correct Answer: (D) Reducing the intensity of competition among competing prey species
They keep dominant competitors in check, allowing weaker competitors to persist.
Q67 of 110
NEET NCERT Line-by-Line
Predators in nature are said to be 'prudent' because:
(A)
Overexploiting prey would cause the prey — and then the predator — to become extinct
(B)
They hunt only at night
(C)
They have low r values
(D)
They only eat sick prey
Show Answer & NCERT Explanation
Correct Answer: (A) Overexploiting prey would cause the prey — and then the predator — to become extinct
If prey go extinct, the predator follows for lack of food.
Q68 of 110
NEET NCERT Line-by-Line
The Monarch butterfly is distasteful to birds because:
(A)
It synthesises the chemical in its adult stage
(B)
It acquires a special chemical during its caterpillar stage by feeding on a poisonous weed
(C)
It has cryptic colouration
(D)
It has thorns
Show Answer & NCERT Explanation
Correct Answer: (B) It acquires a special chemical during its caterpillar stage by feeding on a poisonous weed
The chemical is ACQUIRED as a caterpillar from a poisonous weed — it is not synthesised by the butterfly.
Q69 of 110
NEET NCERT Line-by-Line
Cryptic colouration in some insects and frogs is a means of:
(A)
Warning predators
(B)
Attracting mates
(C)
Camouflage to avoid detection by predators
(D)
Thermoregulation
Show Answer & NCERT Explanation
Correct Answer: (C) Camouflage to avoid detection by predators
Camouflage — being cryptically coloured to avoid easy detection.
Q70 of 110
NEET NCERT Line-by-Line
Approximately what percentage of all insects are known to be phytophagous?
(A)
50%
(B)
75%
(C)
10%
(D)
25%
Show Answer & NCERT Explanation
Correct Answer: (D) 25%
Nearly 25 per cent — feeding on plant sap and other plant parts.
Q71 of 110
NEET NCERT Line-by-Line
The most common MORPHOLOGICAL means of plant defence against herbivores is:
(A)
Thorns
(B)
Nicotine
(C)
Latex
(D)
Cardiac glycosides
Show Answer & NCERT Explanation
Correct Answer: (A) Thorns
Thorns — as in Acacia and Cactus.
Q72 of 110
NEET NCERT Line-by-Line
Calotropis is avoided by cattle and goats because it produces:
(A)
Nicotine
(B)
Cardiac glycosides
(C)
Caffeine
(D)
Quinine
Show Answer & NCERT Explanation
Correct Answer: (B) Cardiac glycosides
Highly poisonous cardiac glycosides.
Q73 of 110
NEET NCERT Line-by-Line
Which of the following is NOT a plant chemical listed by NCERT as an anti-herbivore defence?
(A)
Quinine
(B)
Strychnine
(C)
Insulin
(D)
Nicotine
Show Answer & NCERT Explanation
Correct Answer: (C) Insulin
The NCERT list is nicotine, caffeine, quinine, strychnine, opium. Insulin is an animal hormone.
Q74 of 110
NEET NCERT Line-by-Line
In some shallow South American lakes, which two UNRELATED groups compete for zooplankton?
(A)
Barnacles and starfish
(B)
Goats and tortoises
(C)
Warblers and finches
(D)
Flamingoes and resident fishes
Show Answer & NCERT Explanation
Correct Answer: (D) Flamingoes and resident fishes
Visiting flamingoes and resident fishes — proving unrelated species can compete.
Q75 of 110
NEET NCERT Line-by-Line
Interference competition occurs when:
(A)
The feeding efficiency of one species is reduced by the inhibitory presence of another, even if resources are abundant
(B)
Two species occupy different niches
(C)
Predators remove one competitor
(D)
Resources are strictly limiting
Show Answer & NCERT Explanation
Correct Answer: (A) The feeding efficiency of one species is reduced by the inhibitory presence of another, even if resources are abundant
Interference competition shows that resources need not be limiting for competition to occur.
Q76 of 110
NEET NCERT Line-by-Line
Competition is BEST defined as a process in which:
(A)
Two species eat the same food
(B)
The fitness (r) of one species is significantly lower in the presence of another species
(C)
Two closely related species live in the same habitat
(D)
One species eats another
Show Answer & NCERT Explanation
Correct Answer: (B) The fitness (r) of one species is significantly lower in the presence of another species
NCERT's preferred definition, expressed in terms of r, the intrinsic rate of increase.
Q77 of 110
NEET NCERT Line-by-Line
Gause's Competitive Exclusion Principle states that:
(A)
Mutualists always co-evolve
(B)
Competition never occurs in nature
(C)
Two closely related species competing for the same resources cannot co-exist indefinitely
(D)
Predators always eliminate their prey
Show Answer & NCERT Explanation
Correct Answer: (C) Two closely related species competing for the same resources cannot co-exist indefinitely
The competitively inferior species will be eliminated eventually — but this holds mainly when resources are limiting.
Q78 of 110
NEET NCERT Line-by-Line
The Abingdon tortoise became extinct within a decade after the introduction of:
(A)
Cats
(B)
Rabbits
(C)
Rats
(D)
Goats
Show Answer & NCERT Explanation
Correct Answer: (D) Goats
Goats, on the Galapagos Islands — due to their greater browsing efficiency.
Q79 of 110
NEET NCERT Line-by-Line
Connell's barnacle experiments were conducted on the rocky sea coasts of:
(A)
Scotland
(B)
Australia
(C)
California
(D)
Galapagos
Show Answer & NCERT Explanation
Correct Answer: (A) Scotland
Scotland.
Q80 of 110
NEET NCERT Line-by-Line
In Connell's experiment, the competitively superior barnacle is:
(A)
Chthamalus
(B)
Balanus
(C)
Pisaster
(D)
Cuscuta
Show Answer & NCERT Explanation
Correct Answer: (B) Balanus
The larger Balanus dominates the intertidal area and excludes the smaller Chthamalus.
Q81 of 110
NEET NCERT Line-by-Line
'Competitive release' refers to:
(A)
A parasite leaving its host
(B)
A predator releasing its prey
(C)
A species expanding its range when a superior competitor is experimentally removed
(D)
Two species sharing resources by time-partitioning
Show Answer & NCERT Explanation
Correct Answer: (C) A species expanding its range when a superior competitor is experimentally removed
It is field evidence that competition was actively restricting the species' range.
Q82 of 110
NEET NCERT Line-by-Line
MacArthur's five warbler species co-existed on the same tree because of:
(A)
Predation by a common enemy
(B)
Brood parasitism
(C)
Mutualism
(D)
Behavioural differences in their foraging activities (resource partitioning)
Show Answer & NCERT Explanation
Correct Answer: (D) Behavioural differences in their foraging activities (resource partitioning)
Resource partitioning — different feeding times or foraging patterns promote co-existence rather than exclusion.
Q83 of 110
NEET NCERT Line-by-Line
In general, competition adversely affects which group MORE?
(A)
Herbivores and plants
(B)
Decomposers
(C)
All equally
(D)
Carnivores
Show Answer & NCERT Explanation
Correct Answer: (A) Herbivores and plants
NCERT: herbivores and plants appear to be more adversely affected by competition than carnivores.
Q84 of 110
NEET NCERT Line-by-Line
Which of the following is NOT an adaptation of parasites?
(A)
Loss of the digestive system
(B)
Low reproductive capacity
(C)
Loss of unnecessary sense organs
(D)
Presence of adhesive organs or suckers
Show Answer & NCERT Explanation
Correct Answer: (B) Low reproductive capacity
Parasites have HIGH reproductive capacity — the chance of reaching a new host is low.
Q85 of 110
NEET NCERT Line-by-Line
The human liver fluke requires how many intermediate hosts?
(A)
None
(B)
One
(C)
Two
(D)
Three
Show Answer & NCERT Explanation
Correct Answer: (C) Two
Two — a snail and a fish. The liver fluke is a trematode parasite.
Q86 of 110
NEET NCERT Line-by-Line
The malarial parasite needs which vector to spread to other hosts?
(A)
Tick
(B)
Snail
(C)
Fish
(D)
Mosquito
Show Answer & NCERT Explanation
Correct Answer: (D) Mosquito
The mosquito.
Q87 of 110
NEET NCERT Line-by-Line
Which of the following is an ECTOPARASITE?
(A)
Ticks on dogs
(B)
Liver fluke in the liver
(C)
Tapeworm in the intestine
(D)
Malarial parasite
Show Answer & NCERT Explanation
Correct Answer: (A) Ticks on dogs
Ectoparasites feed on the external surface: lice on humans, ticks on dogs, copepods on marine fish, Cuscuta on hedge plants.
Q88 of 110
NEET NCERT Line-by-Line
Cuscuta, a parasitic plant found on hedge plants, has lost:
(A)
Only its chlorophyll
(B)
Only its leaves
(C)
Both its chlorophyll and its leaves
(D)
Its roots and stem
Show Answer & NCERT Explanation
Correct Answer: (C) Both its chlorophyll and its leaves
It has lost both chlorophyll AND leaves, and derives nutrition from the host plant.
Q89 of 110
NEET NCERT Line-by-Line
Many marine fish are infested with ectoparasitic:
(A)
Lice
(B)
Copepods
(C)
Barnacles
(D)
Ticks
Show Answer & NCERT Explanation
Correct Answer: (B) Copepods
Ectoparasitic copepods.
Q90 of 110
NEET NCERT Line-by-Line
The female mosquito is NOT considered a parasite because:
(A)
It reproduces asexually
(B)
It does not feed on blood
(C)
It does not live in or on the host — it takes only a brief blood meal
(D)
It is beneficial to humans
Show Answer & NCERT Explanation
Correct Answer: (C) It does not live in or on the host — it takes only a brief blood meal
Parasitism means free lodging AND meals. The mosquito gets no lodging and forms no lasting association.
Q91 of 110
NEET NCERT Line-by-Line
Compared with ectoparasites, endoparasites typically show:
(A)
No reproductive specialisation
(B)
Loss of all reproductive organs
(C)
Simpler life cycles and complex morphology
(D)
More complex life cycles, greatly simplified morphology, and high reproductive potential
Show Answer & NCERT Explanation
Correct Answer: (D) More complex life cycles, greatly simplified morphology, and high reproductive potential
Extreme specialisation → complex life cycles, simplified morphology, emphasised reproductive potential.
Q92 of 110
NEET NCERT Line-by-Line
Brood parasitism is best illustrated by:
(A)
Cuckoo (koel) and crow
(B)
Clown fish and sea anemone
(C)
Cattle egret and cattle
(D)
Fig and wasp
Show Answer & NCERT Explanation
Correct Answer: (A) Cuckoo (koel) and crow
The cuckoo (koel) lays eggs in the crow's nest and lets the host incubate them.
Q93 of 110
NEET NCERT Line-by-Line
In brood parasitism, the eggs of the parasitic bird have evolved to:
(A)
Be much larger than the host's eggs
(B)
Resemble the host's eggs in size and colour
(C)
Hatch much later than the host's eggs
(D)
Be brightly coloured to deter the host
Show Answer & NCERT Explanation
Correct Answer: (B) Resemble the host's eggs in size and colour
Mimicry in size and colour reduces the chance of the host detecting and ejecting them.
Q94 of 110
NEET NCERT Line-by-Line
An orchid growing as an epiphyte on a mango branch is an example of:
(A)
Parasitism
(B)
Mutualism
(C)
Commensalism
(D)
Amensalism
Show Answer & NCERT Explanation
Correct Answer: (C) Commensalism
Commensalism (+, 0) — the orchid benefits; the mango is neither harmed nor benefited.
Q95 of 110
NEET NCERT Line-by-Line
Barnacles growing on the back of a whale represent:
(A)
Parasitism
(B)
Mutualism
(C)
Predation
(D)
Commensalism
Show Answer & NCERT Explanation
Correct Answer: (D) Commensalism
Commensalism — barnacles benefit; the whale derives no apparent benefit.
Q96 of 110
NEET NCERT Line-by-Line
The cattle egret forages close to grazing cattle because the cattle:
(A)
Stir up and flush out insects from the vegetation
(B)
Feed the egret directly
(C)
Warn the egret of danger
(D)
Provide shelter from predators
Show Answer & NCERT Explanation
Correct Answer: (A) Stir up and flush out insects from the vegetation
The moving cattle flush out insects the egret would otherwise struggle to find. The cattle gain nothing → commensalism.
Q97 of 110
NEET NCERT Line-by-Line
The clown fish benefits from the sea anemone by gaining:
(A)
Food
(B)
Protection from predators (which avoid the stinging tentacles)
(C)
Oxygen
(D)
Camouflage pigments
Show Answer & NCERT Explanation
Correct Answer: (B) Protection from predators (which avoid the stinging tentacles)
Protection. The anemone does not appear to derive any benefit → commensalism.
Q98 of 110
NEET NCERT Line-by-Line
A lichen is a mutualistic association between:
(A)
A fungus and an insect
(B)
A fungus and the roots of a higher plant
(C)
A fungus and photosynthesising algae or cyanobacteria
(D)
An alga and a bacterium
Show Answer & NCERT Explanation
Correct Answer: (C) A fungus and photosynthesising algae or cyanobacteria
Fungus + photosynthesising algae OR cyanobacteria. (Fungus + plant roots = mycorrhiza.)
Q99 of 110
NEET NCERT Line-by-Line
Mycorrhizae are associations between:
(A)
Algae and fungi
(B)
Bacteria and legume roots
(C)
Fungi and insects
(D)
Fungi and roots of higher plants
Show Answer & NCERT Explanation
Correct Answer: (D) Fungi and roots of higher plants
Fungi + roots of higher plants. Fungus supplies nutrients; plant supplies carbohydrates.
Q100 of 110
NEET NCERT Line-by-Line
In a mycorrhizal association, the PLANT provides the fungus with:
(A)
Energy-yielding carbohydrates
(B)
Water
(C)
Nitrogen fixation
(D)
Essential mineral nutrients
Show Answer & NCERT Explanation
Correct Answer: (A) Energy-yielding carbohydrates
The plant gives energy-yielding carbohydrates; the fungus helps the plant absorb essential nutrients from the soil.
Q101 of 110
NEET NCERT Line-by-Line
The 'fees' plants pay to animals in plant–animal mutualisms are:
(A)
Thorns and toxins
(B)
Pollen and nectar for pollinators; juicy nutritious fruits for seed dispersers
(C)
Only nectar
(D)
Only fruits
Show Answer & NCERT Explanation
Correct Answer: (B) Pollen and nectar for pollinators; juicy nutritious fruits for seed dispersers
Pollen and nectar for pollinators; juicy, nutritious fruits for seed dispersers.
Q102 of 110
NEET NCERT Line-by-Line
'Cheaters' in a plant–pollinator mutualism are animals that:
(A)
Pollinate the wrong species
(B)
Eat the whole flower
(C)
Steal nectar without aiding in pollination
(D)
Lay eggs in the flower
Show Answer & NCERT Explanation
Correct Answer: (C) Steal nectar without aiding in pollination
They take the reward without providing the service — mutualisms must be safeguarded against them.
Q103 of 110
NEET NCERT Line-by-Line
The fig–wasp relationship is best described as:
(A)
Parasitism of the fig by the wasp
(B)
Commensalism
(C)
A loose, non-specific association
(D)
A tight one-to-one mutualism in which a fig species is pollinated only by its partner wasp species
Show Answer & NCERT Explanation
Correct Answer: (D) A tight one-to-one mutualism in which a fig species is pollinated only by its partner wasp species
A tight ONE-TO-ONE mutualism — a textbook case of co-evolution.
Q104 of 110
NEET NCERT Line-by-Line
The female fig wasp uses the fig fruit as:
(A)
An oviposition site, with the developing seeds nourishing its larvae
(B)
A shelter from predators only
(C)
A mating site only
(D)
Only a food source
Show Answer & NCERT Explanation
Correct Answer: (A) An oviposition site, with the developing seeds nourishing its larvae
It is both an egg-laying site and a nursery — the fig offers some developing seeds as larval food in return for pollination.
Q105 of 110
NEET NCERT Line-by-Line
The Mediterranean orchid Ophrys achieves pollination by:
(A)
Offering abundant nectar
(B)
Sexual deceit — one petal mimics the female bee and the male 'pseudocopulates' with it
(C)
Wind dispersal of pollen
(D)
Producing juicy fruits
Show Answer & NCERT Explanation
Correct Answer: (B) Sexual deceit — one petal mimics the female bee and the male 'pseudocopulates' with it
Sexual deceit. Not all orchids offer rewards — Ophrys offers none.
Q106 of 110
NEET NCERT Line-by-Line
In Ophrys, the petal resembles the female bee in:
(A)
Size only
(B)
Shape only
(C)
Size, colour and markings
(D)
Scent only
Show Answer & NCERT Explanation
Correct Answer: (C) Size, colour and markings
An 'uncanny resemblance' in size, colour and markings.
Q107 of 110
NEET NCERT Line-by-Line
Which best demonstrates CO-EVOLUTION?
(A)
Cattle egret and grazing cattle
(B)
Barnacle and whale
(C)
A tiger hunting a deer
(D)
The Ophrys orchid and its male bee pollinator
Show Answer & NCERT Explanation
Correct Answer: (D) The Ophrys orchid and its male bee pollinator
If the female bee's colour patterns change even slightly, pollination fails unless the orchid co-evolves to maintain the resemblance. Fig–wasp is the other classic case.
Q108 of 110
NEET NCERT Line-by-Line
Which orchid pollinators does NCERT specifically name?
(A)
Bees and bumblebees
(B)
Beetles and flies
(C)
Birds and bats
(D)
Moths and butterflies
Show Answer & NCERT Explanation
Correct Answer: (A) Bees and bumblebees
Orchid floral patterns evolved to attract bees and bumblebees.
Q109 of 110
NEET NCERT Line-by-Line
Which of the following pairs is INCORRECTLY matched?
(A)
Cuscuta on hedge plant — Parasitism
(B)
Clown fish and sea anemone — Mutualism
(C)
Cattle egret and cattle — Commensalism
(D)
Lichen — Mutualism
Show Answer & NCERT Explanation
Correct Answer: (B) Clown fish and sea anemone — Mutualism
Clown fish and sea anemone is COMMENSALISM in NCERT — the fish gains protection, the anemone gains nothing.
Q110 of 110
NEET NCERT Line-by-Line
Amensalism is characterised by:
(A)
Both species benefiting
(B)
One species harmed, the other unaffected
(C)
One species benefiting, the other unaffected
(D)
Both species harmed
Show Answer & NCERT Explanation
Correct Answer: (B) One species harmed, the other unaffected
(− , 0) — one is harmed, one is unaffected. NCERT lists it in Table 11.1 but gives no example.