Question

Regularly scheduled physical activity?

decreases stress levels
increases stress levels
improves your diet
prevents injuries

Answer 1

Regularly scheduled exercise can do all of those depending on what /how you do it and who you are.

Answer 2

Well all of it is up to you. Like if you are overweight and exercising is not getting you to loose weight it could increase your stress level or if you are already fit and you exercise your stress level will decrease because of endorphin. If you exercise with precautionary you would prevent injuries.and for the diet it is your mentality as if you want to eat healthier you will try to.