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Date November 2021 Marks available 1 Reference code 21N.1.SL.TZ0.17
Level Standard level Paper Paper 1 Time zone TZ0 / no time zone
Command term Question number 17 Adapted from N/A

Question

What is exchanged between a sealed mesocosm and the surrounding external environment?

A. Energy

B. Water

C. Air

D. Nothing can pass

Markscheme

A

Examiners report

This question had the lowest discrimination index on the paper so some well-prepared candidates must have answered it incorrectly. More than half of candidates thought that nothing can pass in or out of a sealed mesocosm, forgetting that energy will almost certainly be able to pass in or out in the form of heat and probably also in as light. In terms of thermodynamics, a closed system exchanges energy but not matter with its environment.

Syllabus sections

Core » Topic 4: Ecology » 4.1 Species, communities and ecosystems
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Core » Topic 4: Ecology
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