DP Biology (first assessment 2025)

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Question 21M.1A.SL.TZ1.21

Date	May 2021	Marks available	[Maximum mark: 1]	Reference code	21M.1A.SL.TZ1.21
Level	SL	Paper	1A	Time zone	TZ1
Command term		Question number	21	Adapted from	N/A

21.

[Maximum mark: 1]

21M.1A.SL.TZ1.21

The diagram shows the energy flow between five “sinks” in a terrestrial ecosystem.

In a typical terrestrial ecosystem, which trophic level would have the highest biomass?

A. Autotrophs

B. Primary consumers

C. Secondary consumers

D. Detritus feeders

[1]

Markscheme

A

Syllabus sections

C. Interaction and interdependence » C4.2. Transfers of energy and matter » C4.2.6. Autotrophs as organisms that use external energy sources to synthesize carbon compounds from simple inorganic substances

C. Interaction and interdependence » C4.2. Transfers of energy and matter » C4.2.12. Reductions in energy availability at each successive stage in food chains due to large energy losses between trophic levels