NEET (UG)

Practice Test 1 — Organisms and Populations

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct)

Question 1

Birds and mammals are mostly:

Solution: They maintain homeostasis — regulators.

Question 2

Aestivation is dormancy during:

Solution: Aestivation = summer dormancy.

Question 3

The kangaroo rat conserves water by:

Solution: It excretes highly concentrated urine (and uses metabolic water).

Question 4

A broad-based age pyramid indicates a population that is:

Solution: Many young individuals → expanding population.

Question 5

Logistic growth produces a curve that is:

Solution: Logistic growth is sigmoid (S-shaped).

Question 6

The maximum population an environment can support is the:

Solution: Carrying capacity (K).

Question 7

Mycorrhiza (fungus + plant roots) is an example of:

Solution: Both benefit — mutualism.

Question 8

The cattle egret and grazing cattle show:

Solution: Commensalism (+/0): egret benefits, cattle unaffected.

Section B — Assertion & Reason

Question 9

A: Most small animals are conformers rather than regulators.
R: Maintaining a constant internal temperature is energetically very expensive, especially for small bodies that lose heat quickly.

Solution: The high energy cost of regulation for small bodies is why they conform — R explains A.

Question 10

A: Logistic growth is more realistic than exponential growth.
R: Natural habitats have limited resources, so populations cannot grow without bound.

Solution: Limited resources (carrying capacity) is exactly why logistic is realistic — R explains A.

Question 11

A: In commensalism one species benefits while the other is unaffected.
R: An orchid growing on a tree branch gains support and light without harming the tree.

Solution: The orchid benefiting while the tree is unaffected is exactly commensalism — R explains A.

Question 12

A: Two species competing for the same resources may not coexist indefinitely.
R: By Gause's competitive exclusion principle, the competitively inferior species is eventually eliminated.

Solution: Competitive exclusion is exactly why they can't coexist — R explains A.