Which of the following statements about cellular aging is true? ...

[segrsyd]

Which of the following statements about cellular aging is true?
 
  Cells can replicate indefinitely, but errors do occur.
  Aging may be caused by the inevitable loss of the ability of cells to duplicate
  perfectly.
  Damage is caused by free radicals that slow down the cell duplication
  process.
  Cells from adults are able to duplicate more quickly and more times than are
  cells from embryos.

Question 2

The concept of aging as a result of cellular duplication errors is based on the fact that the body's ability to make new cells that are exact copies of the original ones
 
  stops at about age 18.
  stops at about age 80.
  is altered by mutations as time goes on.
  continues unchanged throughout life.

[jliusyl]

Answer to Question 1

Aging may be caused by the inevitable loss of the ability of cells to duplicate
perfectly.

Answer to Question 2

is altered by mutations as time goes on.