At the elbow joint, two bones meet. There is a cavity between the bones and cartilage covers the
ends of each bone for protection. What type of
joint is it?
fixed
synovial
synarthrosis
cartilaginous

 synovial

Explanation:   relating to or denoting a type of joint which is surrounded by a thick flexible membrane forming a sac into which is secreted a viscous fluid that lubricates the joint.

"synovial fluid"

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 .