Which is the most accurate description of molecules?

Molecules are groups of two or more atoms bonded together by chemical forces, forming the smallest identifiable units of a chemical compound. They can consist of the same type of atoms, as in diatomic molecules like O₂, or different types of atoms, such as in water (H₂O). Molecules play crucial roles in determining the properties and behaviors of substances in chemistry and Biology. Their structure and bonding influence their interactions and reactions with other molecules.