Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 35. 

People think children should play sports. Sports are fun, and children stay healthy while playing with others. However, playing sports can have negative effects on children. It may produce feelings of poor self-esteem or aggressive behavior in some children. According to research on kids and sports, 40 million kids play sports in the US. Of these, 18 million say they have been yelled at or called names while playing sports. This leaves many children with a bad impression of sports. They think sports
are just too aggressive.
       Many researchers believe adults, especially parents and coaches, are the main cause of too much aggression in childre’s sports. They believe children copy aggressive 10 adult behavior. This behavior is then further reinforced through both positive and negative feedback. Parents and coaches are powerful teachers because children usually look up to them. Often these adults behave aggressively themselves, sending children the message that winning is everything. At children’s sporting events, parents may yell insults at other players or cheer when their child behaves aggressively. As well, children may be taught that hurting other players is acceptable, or they may be pushed to continue playing even when they are injured. In addition, the media makes violence seem exciting. Children watch adult sports games and see violent behavior replayed over and over on television.

(Adapted from Reading Challenge 2)

The passage is mainly about _________.