Why is your body going through physical and chemical changes?

(MY) body is only going through chemical changes because of my digestive juices, my saliva, and brain functions.

Explanation:

{MY} body isn't going through many physical changes other than my body slowly breaking down on a nuclear level every day slowly just like everybody else that's why nobody dies of old age, its just the teardown of their body eventaully giving out

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.