Final answer:
Carbohydrates are made up of carbon, hydrogen, and oxygen. They are essential for providing and storing energy as well as forming structures in living organisms.
Step-by-step explanation:
Carbohydrates are composed of three elements: carbon (C), hydrogen (H), and oxygen (O). These elements combine in various ways to form simple sugars like glucose, which is a monosaccharide, as well as more complex carbohydrates such as starches, which are polysaccharides. Carbohydrates play crucial roles in living organisms, including providing energy to cells, storing energy, and forming structures like plant cell walls.