MISS PEREGRINES HOME FOR PECULIAR CHILDREN Towards the end of Chapter 4, Jacob’s father remains adamant of his view of Grandpa Portman. What does he resolve and somewhat convince Jacob of as the reasoning for Grandpa Portman’s lack of presence as a father?

Well if you pick a machine to work on and that's gonna be your exercise if you don't stick to that machine your muscle strength your muscle mass rather will change because you haven't been doing it you change something in your exercise routine which changes your body's form of dealing with things for example you might become weaker or stronger depending on what kind of exercises you do in whether or not the machine you picked actually your muscles grow.

The answer would be age 18.