Advocates of the adaptation explanation of sleep believe that the only purpose of sleep is for repair of the body

Lucas has one allele for normal blood cells and one allele for sickle-shaped cells. Lucas' blood cell alleles are

a. recessive. c. heterozygous. b. dominant. d. homozygous.

Grandparents are an example of __________ that can promote children's development

A) unidirectional influences B) third parties C) niche-picking D) a macrosystem