Pls help Test is due very soon

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

Ais a group of individuals of the same that exist together in the same place at the same time

Urgent. the table shows the relative blood flow through some organs in the human body that is, the percentage of blood that flows through a given organ, through which organ(s) does all the blood flow? explain the effect of exercise on blood flow to skeletal muscles.