Question

The prokaryotic cells that were the first to add significant quantities of oxygen to Earth's atmosphere are classified as _____.

a. proteobacteria
b.chlamydias
c.spirochetes
d.gram-positive
e.bacteria
f.cyanobacteria

Answer 1

f. cyanobacteria

Step-by-step explanation:

Cyanobacteria are a group of photosynthetic bacteria. They have the ability to use water as a source of an electron during the process of photosynthesis. Splitting of water produces molecular oxygen that is released into the surroundings. In this way, cyanobacteria release oxygen gas in the air. The primitive atmosphere of the earth was reducing and did not have oxygen gas. The first photosynthetic organisms that could split water during photosynthesis are supposed to be cyanobacteria. These prokaryotes added oxygen to the atmosphere of the early earth and gradually made it oxidative from reducing.