Hormone secretion is usually controlled by systems. a. feedback b. cortical c. portal d. target

The answer here is A. feedback

Specifically, hormone secretions are controlled or regulated by negative feedback system, which helps to keep the hormone  physiologically in an appropriate range or ideal value.

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass