NEET (UG) · Botany, Class 12
Organisms and Populations: NEET PYQ, 2018–2026
Organisms and Populations (Botany, Class 12) has been asked 24 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 3.4 questions a paper, 7% of all Botany questions. It is the 5th most-asked of 17 Botany chapters. NEET 2026 had 3 from it. Last checked 28 October 2026.
Questions per paper
Year by year.
| Year | Questions |
|---|---|
| 2018 | 4 |
| 2020 | 2 |
| 2021 | 5 |
| 2023 | 4 |
| 2024 | 2 |
| 2025 | 4 |
| 2026 | 3 |
From 2021 to 2024 each paper had 200 questions (a Section B with a choice); the others had 180.
Inside the chapter
Topics asked most.
- Interactions11
- Population attributes7
- Population growth models6
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10 Organisms and Populations questions to practise.
Our own questions, written in the NEET pattern and checked, each with an explanation. Pick an option to see the answer.
Q1 · Botany · Organisms and Populations
In a lichen, a fungal partner and an algal partner live together in a close association. Which statement correctly describes the benefit each partner receives?
Answer: (A)
Mutualism is an interaction in which both species benefit. In a lichen, the alga (or cyanobacterium) performs photosynthesis and provides food, while the fungus provides a protected habitat, water and minerals. Only the alga is photosynthetic, so any option that gives the fungus photosynthetic ability is wrong. The lichen is a classic mutualism, so parasitism and competition are not correct.
Q2 · Botany · Organisms and Populations
A sanctuary has 200 deer. In a year there are 40 births, 16 deaths, 10 immigrants and 4 emigrants. What will the population be at the end of the year?
Answer: (A)
Nₜ₊₁ = Nₜ + [(B + I) − (D + E)] = 200 + [(40 + 10) − (16 + 4)] = 200 + 30 = 230.
Q3 · Botany · Organisms and Populations
A population follows the logistic model with carrying capacity K and intrinsic rate of increase r = 0.2 per year. How many years does the population take to grow from K/4 to K/2?
Answer: (A)
Principle: the logistic equation dN/dt = rN(1 - N/K) integrates to N/(K-N) = [N0/(K-N0)] e^(rt), so ln[N/(K-N)] rises linearly with time at rate r. Apply: at N = K/4, N/(K-N) = (K/4)/(3K/4) = 1/3. At N = K/2, N/(K-N) = 1. The change in the logarithm is ln(1) - ln(1/3) = ln3. Time = ln3 / r = 1.0986 / 0.2 = 5.49 years. The interval K/4 to K/2 is not a doubling of N in the exponential sense, so the doubling formula ln2/r does not apply.
Q4 · Botany · Organisms and Populations
In a human population, individuals are grouped into three age classes: pre-reproductive, reproductive and post-reproductive. Which group is the one in which individuals contribute most directly to the next generation?
Answer: (A)
The three age groups are defined by reproductive status. Only individuals in the reproductive age group are capable of producing offspring in the present, so they drive the next generation. Pre-reproductive individuals will contribute later, and post-reproductive individuals no longer reproduce.
Q5 · Botany · Organisms and Populations
A census of a bird population in a sanctuary records 2,000 males and 1,840 females. Expressed in the conventional way, as the number of females per 1000 males, what is the sex ratio of this population?
Answer: (B)
Sex ratio is a population attribute defined as the number of females per 1000 males. Here, females = 1840 and males = 2000. Calculate (1840/2000) × 1000 = 920 females per 1000 males. Check that the numerator is females, the denominator is males, and that the multiplier 1000 is applied. A ratio below 1000 indicates a male-biased population.
Q6 · Botany · Organisms and Populations
A population of 300 individuals lives in a habitat whose carrying capacity is 500. Its intrinsic rate of natural increase is 0.2 per year. By the Verhulst–Pearl logistic equation, what is dN/dt?
Answer: (C)
The logistic equation is dN/dt = rN × (K − N)/K. Here (K − N)/K = (500 − 300)/500 = 0.4, and rN = 0.2 × 300 = 60. So dN/dt = 60 × 0.4 = 24 individuals per year, well below the exponential rate of 60.
Q7 · Botany · Organisms and Populations
Two species with identical resource requirements are grown together in a limited habitat. According to Gause's competitive exclusion principle, what is the usual outcome?
Answer: (B)
Competition is an interaction in which both species are harmed because they draw on the same limited resource. Gause's competitive exclusion principle states that two species with the same niche cannot coexist indefinitely; one is eliminated. Identify the interaction as competition, then apply the principle to the outcome.
Q8 · Botany · Organisms and Populations
A deer population of 1000 individuals records 150 births and 90 deaths in a year, with no migration. The per capita growth rate (r), defined as (births − deaths) ÷ number of individuals, in the year is:
Answer: (C)
The per capita growth rate is r = (natality − mortality) per individual per unit time. Here (150 − 90) ÷ 1000 = 0.06 per individual per year. Because there is no migration, the birth and death figures alone determine the change. Subtract the death rate from the birth rate, not add them.
Q9 · Botany · Organisms and Populations
A population of a mammal contains 480 males and 336 females. Expressed as the number of females per 1000 males, what is the sex ratio of this population?
Answer: (A)
Sex ratio is conventionally given as the number of females per 1000 males. Compute (females / males) × 1000 = (336 / 480) × 1000 = 700. Be careful to put females in the numerator and males in the denominator, and not to confuse the ratio with a difference or a percentage of the total.
Q10 · Botany · Organisms and Populations
A pond had 50 water hyacinth plants at the start of a year, and 15 new plants were added by reproduction during the year. What is the birth rate?
Answer: (B)
Birth rate is the number of births per member of the population: 15 / 50 = 0.3 offspring per plant per year.
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All 24 real NEET questions from Organisms and Populations.
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About Organisms and Populations in NEET.
How many questions come from Organisms and Populations in NEET?
Organisms and Populations (Botany, Class 12) has been asked 24 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 3.4 questions a paper, 7% of all Botany questions. It is the 5th most-asked of 17 Botany chapters. NEET 2026 had 3 from it.
Which topics of Organisms and Populations are asked most in NEET?
Interactions (11), Population attributes (7), Population growth models (6), counted over the papers from 2018–2026.
Is Organisms and Populations important for NEET 2027?
It is in the syllabus in force, so it can be asked. By past papers it ranks 5 of 17 in Botany; use that to decide how much time it gets, not whether to study it.
Where can I solve Organisms and Populations NEET previous year questions?
On Nikaalle, free: sign up and practise every past NEET question from Organisms and Populations with an explanation for each, or sit the full papers timed. The ten questions on this page are our own, written in the same pattern.
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