B. Density has been decreased Or D.
Answer: As each cell differentiates, the <em>DNA </em>changes so that each type of cell has different <em>DNA</em> once it reaches maturity. Mutations in the cells’ nuclei lead to new combinations of <em>DNA</em>, resulting in different shapes and functions in the different types of cells.
Hope this helps!
So you know that your measurements are exactly correct.
Very simple. At rest, you have a number of bpm. After exercise, the heart can't return abruptly to the rest speed, and it keeps a faster rate for a while.
