Among the most common teratogens are

Almost ________ of full-time college students work at least a few hours a week

A) three-quarters B) one-third C) one-fifth D) two-thirds

Compared with agemates who have siblings, Chinese only children feel more emotionally secure because

A) government disapproval promotes tension in families with more than one child. B) Chinese culture is overly focused on the firstborn child. C) families with two or more children are often stressed by financial hardship. D) they do not have to contend with sibling rivalry.