Please choose the correct answer to the question: A scientist put several different plants in a sealed container. Every hour, she checked the oxygen in the container to see if it changed. How did the oxygen in the container most likely change?

Answer1: The amount of oxygen increased. Answer2: The amount of oxygen decreased. Answer3: The oxygen was transformed into water. Answer4: The oxygen was transformed into carbon dioxide.

Answer format: answer1/answer2/answer3/answer4