3. Read these sentences from the article. "I've often wished that I had a time machine to go back and collect a sample of ancient
atmosphere or an ancient bit of seawater," says (Jay] Kaufman. "But we can't. All we
can do is collect rocks that were formed under those waters and under that
atmosphere."
Which conclusion does this statement support?
A. Scientists are skeptical about their ability to determine when oxygen levels in the
Earth's early atmosphere rose.
B. Scientists are unable to study what the Earth was like millions of years ago because
they do not have the materials needed to do so.
C. Scientists study the atmosphere in order to learn what the Earth's seawater was like
millions of years ago.
D. Scientists study rock formations in order to learn what Earth's atmosphere was like
millions of years ago.