Set 3: Central Ideas (Intermediate)
Explanation
PASSAGE
The following text is about the 'Great Oxidation Event'. The Great Oxidation Event (GOE) was a time period when the Earth's atmosphere and the shallow ocean first experienced a rise in oxygen. This occurred approximately 2.4 billion years ago. The rise in oxygen is widely attributed to the photosynthesis of cyanobacteria. While this event eventually paved the way for complex life, it was a catastrophe for the existing anaerobic (oxygen-intolerant) life forms, causing a massive extinction event often called the 'Oxygen Holocaust.'
Why was the Great Oxidation Event considered a catastrophe for some organisms?
Detailed Explanation
Choice B is correct. The text states it was a catastrophe for 'anaerobic (oxygen-intolerant) life forms' causing a 'massive extinction.'
Key Evidence:
• "catastrophe for the existing anaerobic... life forms"
• "massive extinction event"
Why others are wrong: A (Not mentioned), C (Not mentioned), D (Not mentioned).