Answer:
b. Cellular clock is the correct answer.
Explanation:
Cellular clock theory states that cells can divide a maximum of about 75 to 80 times, and that as we age our cells become less capable of dividing.
Cellular clock theory directs on the lifespan of organisms. As the many individual cells do not remain to reproduce continually, so this theory implies that aging of the cells is a result of their reproductive limitation and because of cellular aging.
Cellular clock theory is the theory Leonard Hayflick's that describes the cellular aging mechanism and it suggests that as the cell becomes aged it becomes less effective of dividing.
