What is the simple sugar that serves as the basic subunit of carbohydrates?

• A. Monosaccharide
• B. Amino acid
• C. Polymer
• D. Lipid

Answer: (A)

The basic subunit of carbohydrates is a monosaccharide, a single sugar unit. Monosaccharides are the simplest carbohydrates and serve as the building blocks for more complex carbohydrates. When monosaccharides join, they form disaccharides (two sugars) or polysaccharides (many sugars). Examples like glucose, fructose, and galactose illustrate these single-sugar units that can be linked together to create larger carbohydrate molecules.

Amino acids are the building blocks of proteins, not carbohydrates. A polymer is a general term for a large molecule made of repeating units, which can describe carbohydrates when they form long chains, but it isn’t the simplest sugar itself. Lipids are a separate class of biomolecules and are not sugars.