Answer:
A
Step-by-step explanation:
Carbohydrates are the body's main source of energy, but lipids can also be used, such as when a person is lacking the necessary carbs to provide energy for them.
B - doesn't make sense because enzymes, a type of protein, speed up the rate of reactions
C - doesn't make sense because proteins contain amino acids and peptide bonds
D - doesn't make sense being that's what nucleic acids do