Why are tissue samples from healthy and cancer cells taken from the same patient?

What happens when the cell copies its 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

Which is the graph of the piecewise function f(x)? f(x) = image for option 1 image for option 2 image for option 3 image for option 4