Please help me with this question.

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

The chemical form of energy that is useable by the cell to do work

Anormal appearing couple is found to be heterozygous recessive for albinism both have the genotype aa the gene responsible for albinism is recessive to the normal pigment-producing gene what are the changes of their children being albino