Which organic compound group includes sugars and starches?

The correct answer is carbohydrates, as this group includes both sugars and starches, which are essential sources of energy for living organisms. Carbohydrates are categorized based on their structure and complexity, including simple sugars, known as monosaccharides (like glucose and fructose), and complex carbohydrates, such as disaccharides (like sucrose) and polysaccharides (like starch and glycogen).

Sugars serve as immediate energy sources, whereas starches are polysaccharides that function as energy storage molecules in plants. When consumed, starches are broken down into simpler sugars that the body can utilize for energy. Therefore, the defining characteristic of carbohydrates is their composition of carbon, hydrogen, and oxygen, typically with a hydrogen-to-oxygen ratio of 2:1, similar to water.

The other groups mentioned do not share this characteristic: proteins are composed of amino acids, nucleic acids (like DNA and RNA) are made of nucleotide units that encode genetic information, and lipids primarily consist of fatty acids and glycerol, serving as energy storage and structural components in cell membranes. Thus, carbohydrates are distinctly recognized for including sugars and starches.