NEET Botany — MCQ Practice Questions & Answers

Question 1

The 10% law of energy transfer in an ecosystem states that only 10% of energy is transferred to the next trophic level. What happens to the remaining 90%?

Accepted Answer

Correct answer: B. It is lost through respiration, heat, and decomposition — The remaining 90% energy is lost through cellular respiration, heat dissipation, and decomposition processes at each trophic level, which is why ecosystems have fewer organisms at higher trophic levels.

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A. It is stored in the ecosystem permanently

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C. It is converted to chemical energy

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D. It returns to the sun

Question 2

The concept of 'ecological niche' refers to:

Accepted Answer

Correct answer: B. The specific role and position of an organism in its environment, including its habitat and function — An ecological niche encompasses the organism's habitat, food, behavior, and role in the ecosystem - essentially its complete functional position in the environment.

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A. The geographical area where an organism lives

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C. Only the food preferences of an organism

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D. The number of individuals of a species in an area

Question 3

Which of the following is a characteristic of r-selected species?

Accepted Answer

Correct answer: B. High reproductive rate and short generation time — r-selected species (like rabbits and insects) have high reproductive rates, short generation times, and invest little in individual offspring care, prioritizing quantity over quality.

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A. Long gestation period and high parental care

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C. Large body size and low mortality rate

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D. Stable population and resource conservation

Question 4

The carrying capacity of an environment is best defined as:

Accepted Answer

Correct answer: A. The maximum population size that the environment can sustain indefinitely — Carrying capacity (K) is the maximum population size that an environment can sustain indefinitely given available resources and environmental resistance.

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B. The initial population of an organism

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C. The rate of population growth

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D. The birth rate of a population

Question 5

In India's biodiversity hotspots, which region is NOT included in the recognized biodiversity hotspots?

Accepted Answer

Correct answer: D. Eastern plains of India — India has 4 recognized biodiversity hotspots: Western Ghats, Indo-Burma, Himalayas, and Sundaland. Eastern plains are not recognized as a separate hotspot.

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A. Western Ghats

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B. Indo-Burma region

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C. Himalayan region

Question 6

The concept of 'biomagnification' refers to:

Accepted Answer

Correct answer: B. The increasing concentration of toxic substances in organisms at higher trophic levels — Biomagnification is the process where toxic pollutants (like DDT, mercury) accumulate in higher concentrations in organisms at higher trophic levels due to bioaccumulation.

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A. The increase in organism size over generations

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C. The growth of biological communities

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D. The expansion of habitat range

Question 7

The process by which nitrogen is converted from atmospheric N₂ to usable forms by microorganisms is called:

Accepted Answer

Correct answer: B. Nitrogen fixation — Nitrogen fixation is the conversion of atmospheric N₂ to ammonia (NH₃) or nitrates by nitrogen-fixing bacteria like Rhizobium and Azospirillum.

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A. Nitrification

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C. Denitrification

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D. Ammonification

Question 8

Which of the following best describes 'eutrophication'?

Accepted Answer

Correct answer: B. The process of nutrient enrichment leading to excessive algal growth and oxygen depletion — Eutrophication is the over-enrichment of water with nutrients (phosphates and nitrates), leading to excessive algal growth, dead zones, and oxygen depletion.

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A. The aging and death of water bodies

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C. The cooling of water bodies

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D. The filtration of water by organisms

NEET Botany - MCQ Practice Questions