What are carbohydrates primarily composed of?

Carbohydrates are primarily composed of sugars and starches, which are organic compounds primarily made up of carbon, hydrogen, and oxygen atoms. They serve as a major source of energy for living organisms and are categorized into simple carbohydrates, like monosaccharides (e.g., glucose and fructose), and complex carbohydrates, like polysaccharides (e.g., starch and glycogen).

Sugars are the basic units that can combine to form larger carbohydrate molecules such as starches, which are polymers made up of many sugar units linked together. Starches are important for energy storage in plants and are broken down into sugars for use by animals during metabolism.

The other choices do not accurately represent the composition of carbohydrates. While proteins and fats are essential macromolecules, they do not form carbohydrates. Amino acids and nucleotides are the building blocks of proteins and nucleic acids, respectively, and do not pertain to carbohydrates. Lastly, while vitamins and some chemical compounds are important for various biological functions, they are not components of carbohydrates.