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 helps the person get closer and communicate with that person at face value. Working together strengthens the bond.
Setting a balance of how much you would be eating would be a way that you could prevent a disorder of eating. Setting limits to how much you would be eating, and also, with this in mind, having some stand, and self control would also be a way to prevent eating disorder.