Question

to increase flexibility, you must include
1 stretching exercises
2 weight training
3 cardiovascular exercises
4 muscular endurance exercises

Explanation:

Stretching exercises are specifically designed to improve flexibility by increasing the range of motion of joints and lengthening muscles. Weight training is for muscle strength, cardiovascular exercises for heart and lung health, and muscular endurance exercises for sustaining muscle activity. So stretching exercises are key for flexibility.

Answer:

1. stretching exercises