Answer:
Gas exchange occurs at two sites in the body: in the lungs, where oxygen is picked up and carbon dioxide is released at the respiratory membrane, and at the tissues, where oxygen is released and carbon dioxide is picked up.
Explanation:
It's A. Primary succession :) because Human economics and ecology are linked together because human economics utilizes the ecosystem and the natural resources in older for economics to actually exist. :)))))))
23 hrs 56minutes and 4seconds to be precise
I believe the answers Fungi
