By the time a child reaches the age of around 18 months, (s)he will start rapidly learning new words and associating them with their meanings. In fact, children at this age may learn up to ___ new nouns every day!

Based on research into the reasons why some people are homosexual, while others are heterosexual, most experts would say that homosexuality ________

a. is the result of a "smothering mother." b. is the result of an "absent father." c. is caused by being seduced by an older adult. d. has unknown causes.

Fluid intelligence is to __________ as crystallized intelligence is to __________

a. potential; accomplishment b. experience; capacity c. achievement; experience d. learning; genetic inheritance e. accomplishment; experience