Which system coordinates the body’s response to changes in its internal and external environment? a. lymphatic system. b. nervous system. c. excretory system. d. reproductive system

It is the nervous system! The nervous system is like the control center for the rest of the body. So normally, it sends signals to the rest of the body so it can function properly due to external or internal circumstances. Lets say you are exercising. You start to sweat. Why? The brain is sending signals to the appropriate part of the body to let the function of sweat begin due to your internal and external changes. 

The correct answer of the given question above would be option D. The nervous system is the system that coordinates the body's response to changes in its internal and external environment. It is the organ system that is responsible in the coordination of both voluntary and involuntary functions of the body.