Question

one similarity between carbohydrates and lipids is that they both–
○ contain nitrogen as part of their structure.
○ are composed of fatty acid chains.
○ are made up of chains of smaller subunits.
○ act as enzymes and contain peptide bonds.

Explanation:

1. Analyze Option 1: Carbohydrates (composed of C, H, O) and lipids (mostly C, H, O) do not contain nitrogen in their basic structures. So this is incorrect.
2. Analyze Option 2: Carbohydrates are made of monosaccharides (like glucose), not fatty acid chains (lipids like fats have fatty acid chains). So this is incorrect.
3. Analyze Option 3: Carbohydrates are polymers of monosaccharides (smaller subunits), and lipids (like fats) can be considered as having subunits (glycerol and fatty acids, or for complex lipids, other subunits). So this is correct.
4. Analyze Option 4: Neither carbohydrates nor lipids act as enzymes (enzymes are proteins or RNA) and they don't have peptide bonds (peptide bonds are in proteins). So this is incorrect.

Answer:

C. are made up of chains of smaller subunits.