20 me fast! give me as many benefits as you can find for should/triceps stretch and give me the step on how to do it. number the benefits and steps. make it organized so i can know what is the steps and benefits.

Shoulder stretches
- get warmed up
- move your shoulders in all directions
- move shoulders up down side side

Triceps stretches
- sit or stand to keep your back straight 
- Raise your left arm straight overhead, then bend it so your left hand is on the middle of your upper back. Your biceps and forearm should be touching.
- Pull your left elbow gently toward your right side until you feel a stretch in your left triceps. Hold the stretch for 10 seconds and repeat on the other side.

Cotton with iron probably

What happens to the influenza virus every 20-40 years and why?