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Human influences on the environment

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Question 18

Some industrial processes release warm water into rivers, affecting the aquatic ecosystem. The table below shows the effect of water temperature on the concentration of dissolved oxygen in a river:

Water temperature in $∘C^\circ\text{C}$	Concentration of dissolved oxygen in $mg\text{mg}$ per litre
8	11.84
12	10.43
16	9.21
20	8.15

Calculate the percentage change in the concentration of dissolved oxygen when the water temperature rises from $∘C12\text{ }^\circ\text{C}$ to $∘C16\text{ }^\circ\text{C}$ . Give your answer to one decimal place and show your working.

[3]

Markscheme

Human influences on the environment Questions

IGCSE
Biology
Human influences on the environment

44 exam-style questions on Edexcel IGCSE Biology Human influences on the environment. Each one has a worked solution and a mark scheme showing where the marks go.

Human influences on the environment

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Human influences on the environment

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Question 18

Some industrial processes release warm water into rivers, affecting the aquatic ecosystem. The table below shows the effect of water temperature on the concentration of dissolved oxygen in a river:

Water temperature in $∘C^\circ\text{C}$	Concentration of dissolved oxygen in $mg\text{mg}$ per litre
8	11.84
12	10.43
16	9.21
20	8.15

[3]

Markscheme

Human influences on the environment Questions

IGCSE
Biology
Human influences on the environment

44 exam-style questions on Edexcel IGCSE Biology Human influences on the environment. Each one has a worked solution and a mark scheme showing where the marks go.