DP Biology (first assessment 2025)

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Question 21N.1A.SL.TZ0.17

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Date November 2021 Marks available [Maximum mark: 1] Reference code 21N.1A.SL.TZ0.17
Level SL Paper 1A Time zone TZ0
Command term Question number 17 Adapted from N/A
17.
[Maximum mark: 1]
21N.1A.SL.TZ0.17

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

A. Energy

B. Water

C. Air

D. Nothing can pass

[1]

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.

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