What do macromolecules have in common?< 3

Most common elements in living things are carbon, hydrogen, nitrogen, and oxygen. These four elements constitute about 95% of your body weight. All compounds can be classified in two broad categories --- organic and inorganic compounds. The four main classes of organic compounds (carbohydrates, lipids, proteins, and nucleic acids) are essential to the proper functioning of all living things are known as polymers or macromolecules. All of these compounds are built primarily of carbon, hydrogen, and oxygen but in different ratios.

Explanation:

the answer is d.) homologous; have mammary glands