1. What are the 3 keys to a proper arm swing when learning to hit/spike the volleyball?

Swing your arms back briskly as you bend your knees. When you jump, your entire body should move in one upward swing, putting you in the best possible position to spike the ball. Practice jumping as high as you can and spiking the ball at the height of your jump every time.

since you have not provided the options here i   am going to give you general overview about hormone.hormone are actually the part of endocrine system in our body and produced by the endocrine glands. the hormones act like a chemical messenger   within human body. once produce by the glands they   travel through the blood stream and reach at specific or target tissue and organs   which result in control of our body function. the hormones are specific in their work and work on only the targeted tissue or organ   . with the of hormone endocrine system regulate the heart rate , metabolism, our mood and   growth as well as the development and even the sleeping cycle etc. they actually are the messenger for body cell and organs .