Final answer:
Carbohydrates, specifically monosaccharides like glucose, provide the most energy per molecule.
Step-by-step explanation:
Carbohydrates are the molecules that provide the most energy per molecule. Among the different types of carbohydrates, monosaccharides, such as glucose, are the most readily available sources of energy.
Glucose can be broken down to produce ATP, the primary source of energy used by cells.