Answer:
pulmonary circulation
Explanation:
The pulmonary circulation moves the blood between the lungs and heart. Since the blood carries oxygen the heart pumps it to every body part including the lungs so we can maintain homeostasis.
The growth of plants and formation of land mammals characterized the paleozoic era.
A woodcutter could justify cutting trees for use say in a pioneering situation whereby the pioneer needs shelter and food so trees could be necessary to say construct a small log cabin and table for eating/preparing food at to ensure the survival of the pioneer.
If there isn’t multiple choice I think it is the ones in the center ring (the closest ring to the center) of the atoms