when exercising, if you can talk but not sing, you are engaged in

Moderate Intensity Workout.

Explanation:

When exercising, if you can talk but not sing, you are engaged in Moderate Intensity Workout.

There are three types of intensities while working out. One is Low Intensity, other is Moderate Intensity and the third one is High Intensity. In low intensity workout, you are not burning much calories and can enjoy singing while doing this workout. In Medium or Moderate Intensity workout, you are burning almost 3 to 6 times more calories than while on resting and you can talk but can't sing due to heavy breathing. In High intensity workout, the maximum number of calories are burnt. In this type of workout, you can't even talk while doing the exercise.

it is a i took the test.

answer; by looking at total product,marginal product,and changes in both after changes in inputs