Which best defines cohesion?

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 energy required to vaporize a certain amount of a substance is greater than the amount of energy necessary to raise the temperature of the same amout of that substance by 1 degreee celcius

According to these anatomical structures which two animals are probably most closely related