Question

How did cyanobacteria affect early Earth’s biosphere? Select all that apply. Cyanobacteria allowed organisms that rely on oxygen to evolve. Cyanobacteria stopped the formation of rust in the Earth’s crust. Cyanobacteria preceded the first photosynthetic organisms. Cyanobacteria produced excess oxygen.

Answer 1

Answer:

The correct statements would be

• Cyanobacteria allowed organisms that rely on oxygen to evolve.
• Cyanobacteria preceded the first photosynthetic organisms.
• Cyanobacteria produced excess oxygen.

Cyanobacteria, also termed as blue-green algae are the prokaryotes which are able to perform photosynthesis.

They were the major contributors of oxygen in the atmosphere and thus helped the organisms that rely on oxygen to evolve.

By the process of endosymbiosis, they lead to the origin of plants. The chloroplasts present in green plants is considered as the cyanobacteria living in the plant cell. It helps in photosynthesis and in return plants cell provides shelter to it.

It is believed that the oxygen released from early cyanobacteria reacted with dissolved iron ions to form iron oxide.