Why are producers found at the bottom of the energy pyramid

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

How long does it take a skateboarder going 6.0 m/s to come to a complete stop if she slows down at a rate of 2.0 m/s^2

What do all of the above organisms have in common