<u><em>Subject. A subject in grammar is the first part in a sentence about which the second part, the predicate, tells something.</em></u>
It's pretty much asking you what the characters are like and what's the evidence in the book that says they're that way
Answer:
1The main idea would be "Scientists have lots of evidence to explain why dragons don't exist."
2. Emphasized by the evidence and word choice related to scientific evidence
3. The main idea would be "I have always wondered if dragons existed, and I hope they did."
4. Displayed through the author's nature of questioning and evaluating different kinds of evidence and ideas.
:)
