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

Answer 1

The success of photosynthetic bacteria, particularly cyanobacteria, led to an **increased oxygen concentration** in Earth’s atmosphere. This process, known as oxygenic photosynthesis, produced oxygen as a byproduct, significantly changing the composition of the atmosphere and enabling the evolution of aerobic (oxygen-using) organisms.