* Carbon (C)

* Hydrogen (H)

* Oxygen (O)

These three elements form the basic building blocks of all four major types of macromolecules:

* Carbohydrates: These are primarily composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio (e.g., glucose is C6H12O6).

* Lipids (Fats): Lipids also contain carbon, hydrogen, and oxygen, but they have a higher proportion of hydrogen compared to oxygen.

* Proteins: Proteins include carbon, hydrogen, oxygen, and nitrogen (N). Some proteins also contain sulfur (S).

* Nucleic Acids (DNA and RNA): Nucleic acids contain carbon, hydrogen, oxygen, nitrogen, and phosphorus (P).

While other elements can be present in specific macromolecules, carbon, hydrogen, and oxygen are the fundamental components shared by all.