Question

Biologists are fairly certain that oxygen was built up in the atmosphere by the development of photosynthesis. The production of oxygen and, therefore, the beginning of extensive aerobic life was made possible by the evolution of: _____________________

Answer 1

Answer: The beginning of aerobic life was possible by the evolution of cyanobacteria.

Explanation:

In the early life history, it was said that oxygen was not available for life then not until the evolution of cyanobacteria.

Photosynthetic cyanobacteria were thought to have been the first specie to photosynthesise thereby leading to evolution of multicellular organisms. When cyanobacteria photosynthesize, oxygen is generated and release into the atmosphere which lead to proliferation of multicellular organisms and animal life on it. The evolution of cyanobacteria that lead to release of oxygen was said to have started around 2.3 billion years ago. Cyanobacteria use sunlight to divide water into oxygen and hydrogen and thereby producing there own food using chlorophyll. The oxygen is the byproduct that Is released in the atmosphere

Answer 2

Answer:

Evolution of cyanobacteria

Explanation:

Early earth was reducing therefore there was no oxygen on early earth. Oxygen first came on the earth due to the evolution of cyanobacteria on earth. Cyanobacteria were the first aerobic bacteria on earth.

This bacteria was able to conduct photosynthesis and split water into Hydrogen and oxygen. This oxygen is released in the atmosphere and created the aerobic environment on the earth.  

Cyanobacteria used sunlight energy to split water and by this, they are able to make their own food in the form of carbohydrates. Therefore the correct answer is cyanobacteria.