Answer:
reproduction; protection
Explanation:
Herd behavior is a type of cooperative behavior where individuals function collectively without the need for a centralized direction by gathering into groups with other individuals of the same species. This behavior provides protection from predators, and it is also used for finding food and for having easier access to mates. Herd behavior may be adaptively advantageous, for example, by increasing the effective vigilance of the herd as a whole and also may confuse/intimidate predators. Different animals exhibit a herd behavior including, among others, bird flocks and fish schools.