Attempt this previous-year question. The correct option stays hidden until you choose.
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?
Pick an option to check yourself.
• Correct Answer: C
• Earth's magnetic field has reversed polarity multiple times, last being Brunhes-Matuyama reversal ~780,000 years ago.
• Early Earth atmosphere had negligible free oxygen; photosynthetic cyanobacteria caused Great Oxidation Event.
• Statement 2 is wrong: early atmosphere had CO2 and water vapour, not 54% oxygen.
Attempt Prelims MCQs or open Mains questions by paper — then continue the same bank inside the app with visual decks.
GyanGram