Throughout human history, dreams have terrified, thrilled, and inspired us. But what do they mean? What is their purpose? This essay will provide several explanations from various fields and raise a few questions about dreams that are yet to be answered. What qualifies as a dream exactly? The term dream can refer to our hopes about the future, as in, "One day I dream of visiting Paris." Dreams can also refer to waking fantasies that we largely have control over, such as daydreams. However, the scientific field of oneirology is concerned with what happens when we sleep. "For a dream to be a dream, it has to be an involuntary experience that occurs during the Rapid Eye Movement, or REM, stage of sleep," says neuropsychologist Martin Dyson. "All other uses of the word dream fall outside the domain of science." While all types of dreams are important, it is these nighttime dreams that truly fascinate us.
In a typical night's rest, REM sleep is the stage that happens in the final few hours before we wake up in the morning. In The Science of Dreams and the Dreams of Science, author Isabella Greene explains that this stage of sleep is marked by brain activity that is similar to the brain activity of people who are awake (224). Sleepers have "experiences" during REM sleep, just as waking people do. Some scientists think that during REM sleep the brain clears out our short-term memory and commits important experiences, such as getting a raise or breaking up with our sweethearts, to long-term memory. But why we dream during this process is still a mystery.
Some intriguing, though incomplete, ideas have come from researchers trying to explain why our brains give us such vivid and emotional experiences every night. Sigmund Freud believed that dreams are expressions of memories and anxieties that we avoid thinking about during our waking lives. Carl Jung provided a modern version of the ancient opinion that dreams are messages that help us figure out how to avoid disaster, almost like prophecies. Perhaps the popularity of Jung's interpretation is the reason that many people keep dream journals, wherein they write down their dream experiences before they forget them. After all, if dreams are messages, one had better not ignore them.
But interpreting dreams seems to be a basic human desire, and interpretations of dreams predate modern psychology by many years. The ancient Sumerians, Chinese, and Indians believed that, during dreams, the soul escapes from the body to wander in a spiritual realm. The ancient Greek physician, Hippocrates, theorized that the soul creates its environment when one is asleep and receives its environment when one is awake. Given that modern science has yet to explain dreams, any ancient interpretation is as good as a modern one for now. Perhaps one day that won't be the case.
Until the truth behind dreams is finally revealed, people will continue to speculate about their purpose. And even if the role of dreams is finally articulated, dreams will continue to haunt us, fascinate us, and move us.
Which statement best explains how paragraph 6 makes the essay clearer?

A.
It reminds the reader that dreams have only partially been explored.

B.
It gives specific details about dreams that help develop the author's point of view.

C.
It leaves the reader with an interesting fact that encourages more research.

D.
It summarizes the previous points about the nature and purpose of dreams