Question

Ancestors of modern cyanobacteria probably added significant quantities of oxygen to the atmosphere when they

- became endosymbionts within eukaryotic cells.
metabolized hydrogen peroxide.
- metabolized sulfur dioxide.
- used carbon dioxide as the source for ions utilized in photosynthesis.
- used water as the source for ions utilized in photosynthesis.
- used water as the source for ions utilized in photosynthesis.

Answer 1

Cyanobacteria added significant quantities of oxygen to the atmosphere when they used water as the source for ions utilized in photosynthesis. This led to changes in the planet's atmosphere and the evolution of other life forms. The answer is option D.

Step-by-step explanation:

The ancestors of modern cyanobacteria added significant quantities of oxygen to the atmosphere when they used water as the source for ions utilized in photosynthesis. Cyanobacteria are known for being oxygenic photosynthesizers, and during the process of photosynthesis, they use water as a source of electrons, which is then oxidized to release oxygen. This process contributed significantly to the accumulation of oxygen in the Earth's atmosphere.

Cyanobacteria, also known as blue-green algae, evolved from early phototrophs and began the oxygenation of the atmosphere. Through photosynthesis, they consumed carbon dioxide and released molecular oxygen (O₂) as a byproduct, leading to significant changes in the planet's atmosphere and the evolution of other life forms.