AP BIOLOGY

Detailed explanation-1: -When atoms combine by forming covalent bonds, the resulting collection of atoms is called a molecule. We can therefore say that a molecule is the simplest unit of a covalent compound.

Detailed explanation-2: -Therefore, the attractive forces that hold atoms or ions together to form molecules or compounds are chemical bonds.

Detailed explanation-3: -Atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons.