6. The author asks these questions in the article. "But what can rocks reveal about something as formless as air, much less air that
existed billions of years ago? How does one study the ancient atmosphere when no
samples of it are left to collect?"
Why might the author ask these questions? Consider both the questions themselves
and their context in the article.
A. to get the reader thinking about something that will be explained later in the text
B. to force the reader to come up with ways to study the ancient atmosphere without
collecting samples
C. to invite the reader to learn more about the questions scientists ask themselves
D. to suggest to the reader that it's impossible to learn about the ancient atmosphere
using today's rocks