What is characteristic of a mechanical wave? A.
The wave is capable of transporting its energy through a vacuum.
B.
Particles of the medium regularly and repeatedly oscillate about their rest position.
C.
Particles of the medium move perpendicular to the direction of energy transport.
D.
A medium is required in order for the wave to transport energy.

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.