Im going to have to go with C. they pass through channels in the cell membrane
The body actually performs cellular respiration continuously. The correct option among all the answers that are given in the question is the third option or option "C". The other options that are given are wrong and so can be avoided. I hope the answer has actually come to your help.
The important role of the atmosphere is to supply oxygen, water, carbon dioxide and nutrients. It also protects all living things from extreme temperatures and radiation (protects us from harmful solar rays).
