NEET (UG)

Practice Test 1 — Ecosystem

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

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Section A — MCQ (Single Correct)

Question 1

Net primary productivity equals:

Solution: NPP = GPP − respiration.

Question 2

The biomass available to consumers is the:

Solution: NPP is available to consumers.

Question 3

The detritus food chain begins with:

Solution: DFC starts from detritus (dead matter).

Question 4

According to the 10% law, energy transferred to the next level is about:

Solution: Only ~10% passes to the next trophic level.

Question 5

The always-upright ecological pyramid is the pyramid of:

Solution: The pyramid of energy is always upright.

Question 6

The phosphorus cycle is a:

Solution: Phosphorus is a sedimentary cycle (reservoir = rocks).

Question 7

Pioneer organisms on bare rock are:

Solution: Lichens are the pioneers in primary succession on rock.

Question 8

Decomposition is fastest in conditions that are:

Solution: Warm and moist conditions accelerate decomposition.

Section B — Assertion & Reason

Question 9

A: Food chains rarely have more than four or five trophic levels.
R: Only about 10% of energy passes from one trophic level to the next, so little energy is left for higher levels.

Solution: The large energy loss at each step is exactly why chains are short — R explains A.

Question 10

A: The pyramid of energy is always upright.
R: Available energy decreases at each successive trophic level.

Solution: Decreasing energy at each level is why the energy pyramid is always upright — R explains A.

Question 11

A: The phosphorus cycle has no significant gaseous (atmospheric) phase.
R: Unlike carbon, phosphorus is not released into the atmosphere during respiration.

Solution: No respiratory release into air is exactly why the phosphorus cycle lacks a gaseous phase — R explains A.

Question 12

A: Secondary succession proceeds faster than primary succession.
R: In secondary succession the soil is already present, so colonisation begins quickly.

Solution: Pre-existing soil is exactly why secondary succession is faster — R explains A.