(a)[2]
Fill in the table by writing the names of these gases.
(b)[3]
Oxides of nitrogen are air pollutants that can lead to acid rain. Describe how oxides of nitrogen are formed and suggest the way in which they can cause acid rain.
(c)[2]
Methane adds to the greenhouse effect. State two sources of methane.
(d)[1]
Name one natural process that takes carbon dioxide out of the atmosphere.