When two hormones must be present to achieve full expression of an effect, that interaction is called

Synergism

Explanation:

Synergism means cooperation, and is a term of Greek origin (synergy). Synergy is a work or effort to accomplish a certain very complex task, and to be able to succeed in the end. Synergy is the moment when the whole is greater than the sum of its parts.

In physiology, synergism occurs when the effect of two or more combined chemical agents is greater than the sum of individual effects. Concerning hormones, synergism happens when two hormones must be present for the full expression of an effect. That is, two hormones act for a certain purpose.

Example: FSH (follicle stimulating hormone) and estrogen cause oocyte maturation, but this only occurs if neither acts in isolation.

they kick it to the curb.

explanation:

that current was nasty.