Answer:
giving a friend a birthday present after they have given you one
Explanation:
<em>Reciprocity</em> means the generosity flows both ways.
<em>Between peers</em> means the participants have the same general characteristic age, education, experience, and so on. <em>Friends</em> are often peers.
It is a Spreading disease.
The first one should be "Fight or Flight". I'm not sure about the second one.
The adrenal gland releases adrenaline
D. Stressing defiantly doesn't increase stress. In joints stressing gets released after streching
