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? Scientists are skeptical about their ability to determine when oxygen levels in the Earth’s early atmosphere rose. Scientists are unable to study wh