Which of the following is a correct definition of exercise?

a. planned, structured, and repetitive movement
b. body movement produced by skeletal muscles
c. the body's ability to respond to the demands of physical effort
d. physical activities that increase the heart rate

Planned, structured, and repetitive movement.

Explanation:

Exercise may be defined as the different body movements that increases the strength, flexibility and maintenance of the body. Exercise can be aerobic as well as anaerobic.

The exercise involves the repetitive movement of the body. The exercise should be planned and well sequenced so that one exercise can be repeated after the other exercise. The particular exercise is performed for the particular disease.

Thus, the correct answer is option (a).