the body obtains sugar from food. which system most directly affects blood sugar levels?\no respiratory\no…

Answer:

D. digestive

Brief Explanation:

The digestive system breaks down food to absorb sugar into the bloodstream, directly affecting blood - sugar levels. The respiratory system is for gas exchange, the muscular system uses energy including sugar but not directly affects blood - sugar levels, and the circulatory system transports substances including sugar but doesn't directly affect its levels like the digestive system does.