(a(i))[2]
Describe what is meant by the term excretion.
(a(ii))[2]
Name the process that produces carbon dioxide in living organisms and state the way carbon dioxide is excreted by humans.
(b)[4]
Suggest and explain why the amount of carbon dioxide excreted changes in both animals and plants.
(c)[2]
Explain the effect of a rising concentration of carbon dioxide in the atmosphere.