Answer:
They produce chemicals to fight infection and later produce chemicals to “turn off” the immune system. ( third choice)
This activities help with social life which reduced the percentage of the students dropping out of school, some students to get higher grades and etc.
Answer:
D
Explanation:
as air passes through your system it is filtered, warmed and moistened because of you need that to breath.
You being able to stay warm on cool day is the bodys key
