Please help me i've asked this twice and people wont answer all the questions or even get them right

Which of the following is an important function of child-directed speech? (a) it captures the infant’s attention and maintains communication. (b) it reduces the occurrence of infantile amnesia for the earliest memories of infancy. (c) it reduces the need for reciprocal interaction between caregivers and children. (d) it assists in prolonging rem sleep in infants.

Dementia is most commonly associated with what?

How harmful is it to smoke a pack of cigarettes a week?