Which of the following is an example of social facilitation?
a. the football player who practices hard so he can be on the varsity team
b. the tennis player who is frustrated when the crowd yells at her
c. the bowler who bowls best when he is practicing on his own
d. the olympic bicycle racer who goes faster when he is racing against a person rather than the clock

How does specialization enable countries to trade with one another? a country can make and sell goods affordably and buy goods that it is inefficient at making. a country can make what it chooses and sell its goods to other countries. a country can decide to buy everything it needs from other countries. a country can efficiently make goods that were once difficult to make.