In the context of organic materials, which compound is categorized as a carbohydrate?

Starch is categorized as a carbohydrate because it is a polysaccharide composed of long chains of glucose units, which are simple sugars. Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen, typically with a general formula of (CH₂O)n, where n is the number of carbon atoms. Starch serves as an energy storage molecule in plants and is a significant source of energy in the human diet.

In contrast, fatty acids and triglycerides are classified as lipids, which serve as fats and oils for energy storage and insulation. Amino acids are the building blocks of proteins and are not classified as carbohydrates. Thus, starch stands out as the correct answer due to its structure and role within the carbohydrate group.