86. The primary purpose of the passage is to ____.

1. describe a phenomenon and how it came to be understood
2. discuss a problem and several possible solutions
3. challenge a widely accepted point of view
4. present a new theory and some ways of testing it

87. The reference to "a long flight" (Line 7, Paragraph 1) supports the idea that ____.

1. humans adjust to the natural rhythms around them
2. humans should avoid unnecessary long-distance travel
3. airplane flights are fatiguing for most people
4. not all people synchronize with the local time

88. The "French researcher" in the third paragraph probably chose the location he did primarily to ____.

1. eliminate any effects of the Sun
2. enhance his ability to sleep soundly
3. restrict his access to food and water
4. ensure disruption to his internal clocks

89. Based on the information in the passage as a whole, the "loss of time" (Last Line, Last Paragraph 5) would most likely be "cumulative" in the last sentence for a person who ____.

1. had an extremely irregular pulse rate
2. slept just five hours a night on a regular basis
3. fasted long enough to cause a reduction in deep-body temperature
4. remained in a soundproof, lightproof isolation chamber for several weeks

90. The tone of the passage is best described as ____.

1. argumentative
2. concerned and inquisitive
3. playful and irreverent
4. objective and instructive

(Reference keys.)