Which cylinder of tissue runs along the bottom surface of the penis?

Half of cohabitation relationships end in what period of time?

within the first year within 2 years after 5 years after 8 years

Imagine you hear a report about a heritability study that claims trait X is "50% genetic." Which of the following is a more accurate way of stating this?

a. Fifty percent of individual difference of trait X within a population are due to genetic factors. b. Only half of a population has the trait. c. The trait is homozygous. d. More than 50% of similarities of trait X within a population are the result of genetic factors.