What percentage of sperm is capable of fertilization?

We often decide we like others if they

a. challenge our attitudes b. have a greater proportion of shared attitudes with us c. have a greater number of different attitudes from us d. are different from us in their appearance and attitudes

Carl is a college dropout. According to the text, what might be a strong factor contributing to Carl's early departure from college?

a. Lack of friends b. High socioeconomic status c. Few liberal arts courses d. Lack of financial support