61. In Line 2, Paragraph 1, the word "rival" is closest in meaning to ____.

1. mock
2. dispute
3. nearly equal
4. play with

62. In the second paragraph, the references to animals primarily serve to ____.

1. prove a controversial point about animal behavior
2. contrast with a previous description of animal play
3. emphasize physical similarities between animals and humans
4. show the variety of animal play

63. The findings of "one study" (Line 3, Paragraph 4) primarily support which of the following claims?

1. Play is difficult to study because it takes so many forms.
2. Most animals species tend to begin playing as they approach adulthood.
3. Play is a key factor in the social organization of some animal groups.
4. Research into play may help us understand animals' physiological development.

64. The principle illustrated in Lines 4~-6 Paragraph 5, ("By stalking ... life") is best conveyed by which additional example?

1. Some puppies play only with their siblings.
2. A toddler prefers to play with one particular toy.
3. A lion is trained to jump through a loop.
4. Young monkeys chase each other up and down a tree.

65. Which would be most likely to learn the "essential lessons" mentioned in Line 4 Paragraph 6?

1. A class setting out on a field trip.
2. A young athlete playing on a soccer team.
3. A small child attempting to roller-skate.
4. A bear defending its young.

(Reference keys.)