Only in humans does the __________ compose such a large proportion of the brain relative to other parts

Compared to a person without the APOE4 allele, a person with one APOE4 allele has _____ times the risk of developing Alzheimer-type dementia in old age while a person with two APOE4 alleles has _____ times that risk

8; 20 20; 8 80; 200 200; 80

All of the following are reasons that the classification of sexual orientation is difficult EXCEPT which of the following?

A) Same-sex sexual experience can happen in the absence of heterosexual outlets. B) People with homoerotic interests typically do not shift interests over time. C) Some gay males and lesbians may maintain male-female sexual activity while maintaining a gay sexual orientation. D) Some people do not act on their sexual attractions.