The smallest unit that retains the properties of an element is a(n)

The given blank can be filled with the atom.  

An atom is the minutest component of a matter, which exhibits the characteristics of a chemical element. Every liquid, solid, plasma, and gas comprises ionized or neutral atoms.  

The atoms are extremely small, the usual sizes are about 100 picometers. Each atom contains a nucleus and one or more electrons combined with the nucleus. The nucleus is formed of one or more protons and usually a same number of neutrons.  

endo:

regulates body hormones, aldosterone, vasopressin

neural:

signal, regulates body using electric signals, reflex

endo has to do with hormones; aldosterone and vasopressin are both hormones. i also had this question and got it right : d

genetic variation will increase because of a new habitat and food source.

explanation: