Which piece of information about carbon dioxide and methane is correct?
- Aformed when vegetation decomposes (carbon dioxide ✓, methane ✗)
- Bgreenhouse gas (carbon dioxide ✓, methane ✓)
- Cpresent in unpolluted air (carbon dioxide ✗, methane ✗)
- Dproduced during respiration (carbon dioxide ✗, methane ✓)