What is the most abundant type of element in the air? oxygen helium nitrogen carbon dioxide
nitrogen
What is the second most abundant type of element in the air? nitrogen helium carbon dioxide oxygen
oxygen
What type of air do plants need? carbon dioxide oxygen argon nitrogen
carbon dioxide
What type of air do animals need? nitrogen helium carbon dioxide oxygen
oxygen
About how much oxygen is in the air? 79% 37% 50% 21%
21%
Which one of these uses wind? kites basketballs tennis
kites
Which activities do humans do to cause air pollution?
...
Name two things we can do to reduce air pollution
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