SOLAR SYSTEM

Detailed explanation-1: -Although cyanobacteria are the dominant primary producers in modern stromatolites and other microbialites, the oldest stromatolites pre-date geochemical evidence for oxygenic photosynthesis and cyanobacteria in the rock record.

Detailed explanation-2: -Cyanobacteria possessed the machinery to utilize water as a fuel source by oxidizing it. More significantly, the by-product of photosynthesis happened to be oxygen. Stromatolites are large, layered structures built up by mats of cyanobacteria.

Detailed explanation-3: -Scientists think that algae first evolved approximately 2.7 billion years ago, and soon after this oxygen began to exist in the atmosphere. Photosynthesis by primitive plants and algae released oxygen, which gradually built up in the atmosphere.

Detailed explanation-4: -Stromatolites are sedimentary rocks formed by the growth of layer upon layer of cyanobacteria, a single-celled microbe that gets energy through photosynthesis, releasing oxygen as a by-product.