The most important factors involved with good health are those associated with:

The most important factor that is involved with good health are those associated with life style because this will affect the person’s life in terms of his or her health and how he or she will live his or her life, shape it in order to make him or her live long and happy.

the answer is c because it is most logical.

yes, because even though a theory has a  lot of evidence to support it, it is not always true