What do plants use for energy?
glucose
water
light
fructose
What do animals such as clams and oysters extract from the water to build their shells?
carbon
hydrogen
fructose
silicon
Why does Earth have a lower amount of carbon in the atmosphere than planets such as Venus and Mars?
1 answer
Earth's atmosphere contains more oxygen, which reacts with carbon to form carbon dioxide. Venus and Mars have much less oxygen in their atmospheres, so more carbon is able to remain in the atmosphere.