HELP!! which wave requires a medium to travel through?

a. microwave
b. light wave
c. electromagnetic wave
d. sound wave

which one?

Edward tolman explained the results of his study by theorizing that the rats were learning about the maze during every trial but they a. were agitated because other groups were getting reinforcement b. could not remember how to demonstrate it without reinforcement c. were not motivated to demonstrate it without reinforcement d. seemed to be too lazy to actually work without reinforcement

Aregion of space in which a measurable gravitational force is indicated by the force exerted on a test mass is called

The two required components for a generator are