Q57.
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?
Answer
C
Explanation
Statement 1 is correct: Earth has settled in the last 20 million years into a pattern of a magnetic pole reversal about every 200,000 to 300,000 years. Statement 2 is not correct: When Earth formed 4.6 billion years ago, its atmosphere formed mainly from volcanic gases including hydrogen sulfide, methane, and high carbon dioxide (not 54% oxygen). Statement 3 is correct: When living organisms originated (especially photosynthetic organisms), they modified the early atmosphere - reducing CO2 and producing oxygen.