1. a mechanical wave
a. carries energy from one place to another
b. moves through solids, liquids, and gasses
c. is created when a source of energy creates a vibration
d. all of the above

2. in refraction when a wave travels from one medium to another
a. changes speed
b. stays in step
c. always moves in the same direction
d. travels in the opposite direction

plzzz me !
i understand that it is wrong to give answers but i need them for unit 3 lesson 12 , me graduating rides on this