Arrange the following in order from the smallest to largest level of organization: Peptide
Protein
Amino acid
Polypeptide

Amino acid, peptide, polypeptide, protein

Explanation:

Amino acids make up a peptide. A group of peptides form a polypeptide chain. A protein is a group of polypeptides.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.