Please choose the correct answer to the question: Liam lives in the Northern Hemisphere of Earth and plays in the snow in December. His friend lives in the Southern Hemisphere of Earth and plays at the beach in December. What is the best explanation for why this is possible?

Answer1: tilt of Earth on its axis Answer2: rotation of Earth on its axis Answer3: revolution of Earth around the Sun Answer4: revolution of the Moon around Earth

Answer format: answer1/answer2/answer3/answer4