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 ?

Statements 1 and 3 are correct because paleomagnetic records confirm that Earth's magnetic field reverses at irregular intervals, and early life forms like cyanobacteria significantly modified the atmosphere through the production of oxygen. Statement 2 is incorrect because the early atmosphere was a reducing environment rich in carbon dioxide and water vapor but devoid of free oxygen, which only accumulated much later via photosynthesis. The core concept tested is the co-evolution of Earth's physical systems and biological life over geological time.