Page 20 - 新思维科学活动用书9 样章

1.3 The carbon cycle

1.3 The carbon cycle

Exercise 1.3 Completing a carbon cycle diagram

The diagram shows part of the carbon cycle.

carbon dioxide
in the air

carbohydrates carbon compounds in
in decomposers fossil fuels, e.g. oil and coal

carbohydrates carbohydrates
in animals in green plants

Focus

1 On the diagram, write these labels next to the correct arrows:
R next to the three arrows that show respiration

P next to the one arrow that shows photosynthesis
C next to the one arrow that shows fossil fuels being formed
D next to the two arrows that show decomposition
F next to the one arrow that shows feeding.

Practice

Hydrogencarbonate indicator changes colour according to how much carbon dioxide there is in it.
• The indicator is purple when there is no carbon dioxide.
• The indicator is red when there is a low concentration of carbon dioxide.
• The indicator is yellow when there is a high concentration of carbon dioxide.

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