Which of the following will lead to speciation? a)variation in gene pool b)lack of mutations c)absence of natural selection

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

Pulmonary arteries carry highly oxygenated blood. true or false?

The term facultative anaerobe refers to an organism that