Jennifer and michael are typical of the participants in a longitudinal study that revealed most bad health habits engaged in during adolescence in emerging adulthood. they both smoke, often drink too much, and seldom stick with an exercise plan.

increased

Explanation:

From the question , most of the bad health habits , increases , during the age of adolescence , in the age of  adolescence a child gets converted into an adult , the age of puberty arises .

The age group of  adolescence is very crucial for any person , whether be a girl or a boy , during this very age bad habits like smoking , drinking , drugs surrounds and get trapped in these habits .

Same is the case with Jennifer and Michael , as given in the question .