Question

which is a difference between proteins and carbohydrates and fats?

proteins are macromolecules; carbohydrates and fats are not.

proteins are composed of monomers; carbohydrates and fats are not.

carbohydrates and fats contain carbon, hydrogen, and oxygen; proteins do not.

excess carbohydrates and fats are stored; excess proteins are not.

Explanation:

• Analyze Option 1: Carbohydrates (e.g., polysaccharides) and some fats - related molecules can be macromolecules, so this is incorrect.
• Analyze Option 2: Carbohydrates are made of monomers (monosaccharides), and fats (lipids) have monomer - like units (e.g., fatty acids and glycerol), so this is incorrect.
• Analyze Option 3: Proteins also contain carbon, hydrogen, and oxygen (along with nitrogen, etc.), so this is incorrect.
• Analyze Option 4: The body stores excess carbohydrates (as glycogen or fat) and excess fats (as adipose tissue), while excess proteins are not stored in the same way (they are broken down and the nitrogen is excreted, and the remaining carbon - based parts are used for energy or converted to fat for storage in a less direct way compared to carbs and fats). So this statement is correct.

Answer:

D. Excess carbohydrates and fats are stored; excess proteins are not. (Here we assume the options are labeled A - D in order as presented in the question, with the last option being D)