Answer:
C
Explanation:
It is known as lactation. The suckling action of an infant produces prolactin, which leads to milk production; more suckling leads to more prolactin, which in turn leads to more lactation. This is a positive feedback system as the product (milk) produces more suckling and more hormone. When the child is no longer breast feeding, the prolactin drops off and milk production goes down.
Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.
