B.
PART A: Which of the following best identifies the central idea of this text?
A. Living creatures have thousands of different cells with genes that determine cel
functions and growth.
The body produces less cells as you get older because adult cells do not need
genes to give them instructions.
Each cell in the human body is unique and stem cells can turn into any cellar
any point in time to replace weak cells.
Stem cells are different from other cells because they stop copying other cells
once a baby is born.