Question

which process in living things evolved as oxygen levels increased in earths atmosphere?
fermentation
aerobic respiration
photosynthesis
glycolysis

Explanation:

1. Analyze each process:

• Fermentation: An anaerobic process (does not require oxygen), so it would have evolved before oxygen levels increased significantly.
• Aerobic respiration: Requires oxygen. As oxygen levels in the atmosphere increased, organisms evolved to use oxygen in respiration, so aerobic respiration is the process that evolved with increasing oxygen.
• Photosynthesis: Produces oxygen, but the question is about a process that evolved as oxygen levels increased (using oxygen), not producing it.
• Glycolysis: An anaerobic process (part of both aerobic and anaerobic respiration but can occur without oxygen), evolved earlier.

1. Conclusion: Aerobic respiration requires oxygen, so it evolved as oxygen levels in the atmosphere increased.

Answer:

B. aerobic respiration