I believe it is the connective tissues
Some examples are the mouth, nose, eyes, lungs, stomach, and the trachea.
The importance of physical activities can help you get motivated, stress relief, and even help with your immune system.
Some questions Jim should ask to protect his safety:
Who else is coming?
Will there be parental supervision? (If he's under 18)
Will there be any alcohol or drugs?
Where are they meeting?