a lipid that coats lactose molecules an ability to produce lactose internally an enzyme that catalyzes lactose breakdown a tolerance to lactose developed during childhood
I gave my students this multiple choice question: Some individuals are unable to digest the lactose found in the milk of cows. The digestive systems of these individuals most likely lack which?

Only one answer is correct among these 4 choices:
- a lipid that coats lactose molecules
- an ability to produce lactose internally
- an enzyme that catalyzes lactose breakdown
- a tolerance to lactose developed during childhood

Could you tell me which one is correct?

an enzyme that catalyzes lactose breakdown