According to Webster Dictionary, Homeostasis is a relatively stable state of equilibrium or a tendency toward such a state between the different but interdependent elements or groups of elements of an organism, population, or group.
In simpler words, homeostasis is a period in time where things are relatively balanced and able to adapt to change without causing a lot of problems. I found a few examples involving the human body including body temperature, glucose levels and fluid volume. If you need an extra explanation, I will link the site if examples down below. (:
Happy studying!
http://www.brighthub.com/science/medical/articles/112024.aspx
A-Progressive tense Example: I bike everyday. "I am biking today."
Hi there!
I believe that the answer that you are looking for is C: Progressive.
Hope this is right!