Consider the following statements: 1. The Earth's magnetic field has reversed every few hundred thousand years. 2. When the Earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide. 3. When living organisms originated, they modified the early atmosphere of the Earth. Which of the statements given above is/are correct?

1. Statement 1 is correct. Paleomagnetic evidence from rocks indicates that the Earth's magnetic field has undergone numerous reversals throughout geological history. These reversals are irregular, but they occur on average every few hundred thousand years. 2. Statement 2 is incorrect. When the Earth was created more than 4000 million years ago, its early atmosphere contained negligible free oxygen. It was primarily composed of gases like water vapor, carbon dioxide, nitrogen, methane, and ammonia, released through volcanic outgassing. The claim of 54% oxygen and no carbon dioxide is factually wrong. 3. Statement 3 is correct. The origin and evolution of living organisms, particularly photosynthetic microbes like cyanobacteria, significantly modified the early atmosphere of the Earth. Through photosynthesis, they consumed large amounts of carbon dioxide and released oxygen, gradually transforming the atmosphere into the oxygen-rich one we have today.