Why would joint damage be associated with rapid growth and low testosterone levels?

Since testosterone is responsible for bone mass and muscle development, lack of this in male causes joint damage and muscle pain.

Explanation:

In a male body, the role of testosterone is not only linked to sexual behaviour but also to several other vital functions such as development of bones and muscles, hair growth, voice deepening etc. Thus, when a male is reported with the issue of low testosterone, there are high chances of this individual   experiencing muscle aches, joint pains and reduced bone mass. This lack of testosterone in later stages causes arthritis in old age male.

the answer is:

carbon dioxide

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.