Question

How did the success of photosynthetic bacteria change Earth’s atmosphere?(1 point)
Responses

decreased hydrogen concentration
decreased hydrogen concentration

increased hydrogen concentration
increased hydrogen concentration

decreased oxygen concentration
decreased oxygen concentration

increased oxygen concentration
increased oxygen concentration

Answer 1

The success of photosynthetic bacteria, particularly cyanobacteria, significantly changed Earth's atmosphere by **increasing oxygen concentration**. Through the process of photosynthesis, these bacteria converted carbon dioxide and water into glucose and oxygen, greatly enriching the atmosphere with oxygen over geological time. Thus, the correct response is:

**increased oxygen concentration**.