Your best friend has been acting differently lately. he or she is not interested in doing anything that he or she normally enjoys. he or she is hanging out with a different group of people at school and you suspect she might be using drugs. how would you safely handle the situation

Sounds like depression, Safely handling the situation you could talk to your friend and offer them help. You could go to the guidance consular and tell them your friend may be using drugs and that you want them to get the help that they need. 

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.