Question

1. what organism is responsible for the beginning of the production of oxygen in the atmosphere?

mosses
ferns
cyanobacteria
algae

Explanation:

Cyanobacteria (blue-green algae) were the first organisms to perform oxygenic photosynthesis, which began adding oxygen to Earth's early atmosphere over 2 billion years ago, long before mosses, ferns, or other algae emerged.

Answer:

cyanobacteria