Achieving flexibility can Reduce risk of injury
Help you lose weight
Increase your stress
Cause muscle soreness

Achieving flexibility can  reduce risk of injury.

Explanation:

Muscle and joint flexibility is a feature that allows for improved physical movement, with less risk of physical damage.

Increased or improved flexibility has been associated in athletes with a decreased risk of injury, so many physical practices promote exercises to improve this characteristic.

In terms of sports, flexibility allows the muscles to perform optimal work and the joints to obtain their maximum range of motion, which translates into an ideal physical activity with less health risk.

The other options are not related to flexibility because:

i'm pretty sure questions like these aren't allowd.   but, sure.   i can and talk : ))