Simple one-celled cyanobacteria like organisms appeared on earth

Simple one-called cyanobacteria-like organisms developed on earth

The first organisms appeared on earth were

The first organisms appeared on earth were

Assertion: They were cyanobacteria- like organisms, which in ancient time added oxygen to the atmosphere. Reason: Cyanobacteria were photoautotrophic.

First photosynthetic organisms to appear on earth were

First photosynthetic organisms to appear on earth were