Which statement about the U.S. population is incorrect?

Which statement about the U.S. population is incorrect?
 a. In 1900, 4 of the population was over age 65
  b. Today, 15 of the population is over age 65
  c. We expect to see the percentage of Americans over age 75 double.
  d. By the year 2050, 20 of the population will be over age 65.

---

The cross-linking theory of aging holds that the stiffening of body proteins eventually breaks down bodily processes.
  Indicate whether the statement is true or false

---

When cells cease dividing, they immediately die.
  Indicate whether the statement is true or false

---

Menopause usually signals an end to a women's sex life.
  Indicate whether the statement is true or false

---

Many men can still father children in their 70s and 80s.
  Indicate whether the statement is true or false