UPSC CSE Prelims 2018 Q57 — Geography PYQ with Answer

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?