A satellite does not need any energy to revolve around the earth, why ?

A satellite rotates around the earth by using earth's gravitational force as centripetal force. Also as there is no air in space, it does not have to work against air resistance. Hence it doesn't lose any energy while rotating. So it does not require fuel to rotate around the earth.

b. latent learning (the word "latent" itself means something that exists but isn't obvious, only under certain conditions! )

the word that best describes martin luther king jr.'s tone in the video is dignified

martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer