An essay on save life save earth to be written by a class 12 student (please give short and sweet points)​

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

Most animal cells membranes have proteins that pump ions out of the cell and potassium ions into the cell

The cretaceous period spanned the time interval between and 65 million years ago. 250 million 144 million 75 million 200 million