What two chromosomes do males have for gender? x chromosomes y chromosomes x and y chromosomes sperm cells do not contain sex chromosomes

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

Ture or false evidence for evolution includes millions of fossils

In each transformation of energy , some energy what?