Fill in the blank with the best answer.

1		are negatively charged ions.
2		and neutrons are found in the nucleus of an atom.
3		Atoms that complete their outer shell by sharing electrons form molecules held together by bonds.
4		A chemical that is the result of lost electrons is called a(n) .
5		A reaction that involves breaking a molecule down into smaller pieces is called a(n) reaction.
6		A reaction in which molecules break apart, then form new molecules by combining in a different manner is called a(n) reaction.
7		Compounds that break apart in water forming charged particles are called .
8		The most abundant substance in the human body is .
9		Compounds that contain carbon and hydrogen are called compounds.
10		A substance that assists in maintaining the pH of body fluids is called a(n) .
11		A chain of many carbons with hydrogen side groups and an OH group at one end is called a(n) .
12		The bodies best source of energy is a carbohydrate called
13		Cholesterol is one type of a large group of lipids called
14		Our genes are stored in compounds called .
15		is special nucleotide with extra phosphate groups that can be used by cells to do work.