Discuss factors that can lead to speciation?

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

Ascientific idea becomes valid when it is what?

Why is it to call the calvin cycle the light independent reactions vs the dark reactions