Athletes warm up to ensure their joints are flexible. flexible joints are
a. naturally occurring as you move further into your fitness program.
b. important to prevent athletic injury.
c. important so you can run faster or reach farther.
d. only a concern for cross-training athletes.

The importance of warming up is that warm-up sessions is that they are B. important to prevent atletic injury. Athletes and body builders aim to increase blood flow in their joints and muscles when they warm up. The increased flexibility prevents injuries and ensures a complete range of movement during vigorous sessions of exercise.

"air pollution" is the correct answer i believe