Does life need oxygen? Plant life clearly doesn’t. In fact, green plants need carbon dioxide for photosynthesis, making oxygen as the by-product. But does animal life need oxygen? The first clue to this puzzle came in 1924. German biochemist Otto Warburg made an astounding observation—cancer cells didn’t need oxygen to grow. While Warburg never figured out why this was the case, his observation was important enough that he won the 1931 Nobel Prize in Physiology or Medicine.
