3.The human body has many cells that are deep inside the body. For this reason, the human body requires (1) a transport system and other organs (2) carbon dioxide from the air (3) the breakdown of glucose by the digestive system

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