Homeostatic mechanisms :

a. keep variables exactly at the set point.
b. act to keep values out of the normal range.
c. help to keep a relatively constant internal environment in the body.
d. usually operate by positive feedback.
e. produce most disease conditions.

C

Explanation:

The main mechanisms of homeostasis are body temperature, body fluid composition, blood sugar, gas concentrations, and blood pressure. These are all things that involve "keeping a relatively constant internal environment in the body".

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