Answer:
it exchanges oxygen and carbon dioxide
Explanation:
You inhale oxygen and exhale carbon dioxide
A mathematical model of a food web helps you better understand portions, and track the structure of how the web is flowing. The food web could also help because it helps predict things.
An eon is 1.05 billion years and an era is 350 million years
Not entire sure because I haven't taken human anatomy but I'd guess it would have to be the digestive enzymes breaking it down
Answer: it lets for room for more buildings to be built
Explanation: