What is the central idea of the first section:
When and How Often Do We Dream?
REM sleep was discovered by researchers at
the University of Chicago.
People dream every night during a sleep cycle
called REM sleep.
People dream from 5 to 20 minutes within each
sleep cycle.
Most people experience at least one hour of
REM sleep every night.

Explanation:

Night after night Eugene Stravinsky had been working late. ... The mind in REM sleep teems with vivid dreams; some brain structures consume ... Stravinsky had the idea of studying all eye movements in sleeping infants, and with ... he initially discerned a 20-minute period in each infant's sleep cycle in which there was no ...

a) walter looks unhealthy

the correct answer is:

from context clues heliotrope is probably a flower.

a heliotrope are peruvian plants that have small purplish plants.