Why was the evolution of cyanobacteria such a significant event in earth’s history?

It was a significant event in Earth’s history because the cyanobacteria made the oxygen that we breathe today.

Cyanobacteria is a type of bacteria that is aquatic (lives in the water) and photosynthetic (manufactures their own food). These organisms are usually unicellular, and grow in colonies. Cyanobacteria were particularly important in the development of our planet, as they generated the oxygen atmosphere that we need to survive. This took place during the Archaean and Proterozoic Eras. Cyanobacteria were also very important in the development of plants.

i think it because equal matrices have equal dimensions, only square matrices can be symmetric. for all indices and . every square diagonal matrix is symmetric, since all off-diagonal elements are zero. in linear algebra, a real symmetric matrix represents a self-adjoint operator over a real inner product space.