Adult stem cells cannot repair and replace cells in a animal true or false?

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 breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above

Isolated volcanic peaks on the ocean floor are