Which of the following is used to calculate a stream's discharge

What re the two main phrases of the cell cycle.

Imagine ? person stepping on a pin and pulling his or her foot way look at the réfléchir arc of the scenarios below

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point