How be cells become differentiated in the embryo?
a) they get larger.
b) they turn on different sets of genes.
c)they move.
d)they change shape.

Look at the graph about the barriers to working out. what would 20 percent of the population report as a barrier for working out? inability to devote thirty minutes a day to working out lack of interest with creating a detailed workout schedule not having enough money to pay for yearly gym membership living in a community that does not have parks or a gym facility