HELP ASAP PLS I DONT UNDERSTAND #2, 3 and 5 BUT IF U CAN HELP WITH ALL PLS DO

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

What is the problem in this article? what solution does the article propose?

What is the ecological role of food chains and food webs