Which of the following is uncommon and demands a medical check-up?

Your text discusses a phenomenon in which children between 9 months and 15 months engage in "crib speech", in which they talk while alone in a room. The point of this example was to illustrate

a. a behavior that tends to result in methylation b. a negative consequence of children failing to get enough attention from caregivers c. how children shape their own development d. how behavioral change can appear to be discontinuous but actually be continuous

Fifty-year-olds can expect to retain ______ percent of the muscle strength they had at age 20

30 50 70 90