Due to the constant random motion of its atoms and molecules, a substance will exhibit net movement from a region where it has a higher concentration to a region where it has a lower concentration.
this net movement is called

The net movement is called diffusion.

Explanation:

Diffusion is the net movement of substance from region of higher concentration to a region of lower concentration.

The movement is due to constant and random motion characteristics of atoms ,ions and molecules due to kinetic energy. It continues until the concentration of substance is uniform.

the answer to your question is sperm

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.