AP BIOLOGY

Detailed explanation-1: -A molecule is the smallest particle of an element or compound that can exist independently. It is formed when two or more atoms are bonded chemically. For example, the element hydrogen cannot exists independently as a single atom therefore two hydrogen atoms bind chemically to form H2 molecule.

Detailed explanation-2: -A molecule is two or more atoms connected by chemical bonds, which form the smallest unit of a substance that retains the composition and properties of that substance. Molecules form the basis of chemistry.

Detailed explanation-3: -Answer and Explanation: A compound is defined as two or more atoms of different elements bonded together.

Detailed explanation-4: -A substance consisting of atoms or ions of two or more different elements in definite proportions joined by chemical bonds into a molecule is known as compound. The elements cannot be separated by physical means. Water, for example, is a compound having two hydrogen atoms and one oxygen atom per molecule.