What two organ systems are most involved in controlling the negative feedback systems of the body?

The respiratory system as well as circulatory system (hormonal system) are involved in controlling the negative feedback of our body.

Explanation:

The respiratory system helps in controlling the negative feedback in such a  way that if CO2 level increases in body the system acts in such a way so as to decrease  its level in body . the system attains a normal level by  increasing the blood circulation and increasing the breathing level forcing CO2 outside of our body.

in case of circulatory system, the blood has several hormones released from glands . the most common example is Insulin and Glucagon .

if a person is hypoglycemic then glucagon concentration increases and blood glucose concentration returns to normal and if a person has hyperglycemia then insulin level increases which in turn increases glucose uptake from body and body returns to normal level.

the answer is c on e2020, bud.