Physical aggression is one of the misbehaviors because it can lead to physical harm.                a.  least complex      b.  least dangerous      c.  most dangerous      d.  most acceptable

Without even knowing for sure, C. Just sounds right given the context.

Afew buddies come over to your house to hang out. they notice you're struggling in school, perhaps you have to rely on to pass your class, but you can't absorb the knowledge. they could positively reinforce getting a tutor and working with you, dedicating more time to the areas of struggle and less on hanging out to better yourself.secondly, say you're the victim of bullying. you're afraid to tell an adult because of possible repercussions from the bully himself. your friends encouraging you and pushing you towards telling an adult for your safety is another example. 

Pretty much everywhere: walking requires friction, driving around curves, steering a car with the steering wheel, starting fire with a stick, objects moving along a conveyer belt.