Question

which is associated with ‘Rich in Oxygen​

Answer 1

Answer:

Answer is

• Blood
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Answer 2

Answer:

BLOOD

Explanation:

It may have been unexpectedly easy for the air to become rich in oxygen. A new simulation of the rise of oxygen suggests that it was driven by the planet itself, and needed little help from living organisms.

The finding implies that planets with oxygen-rich atmospheres could be more common than we thought. “It’s easier, not just for our planet, but possibly for others as well,” says Lewis Alcott at the University of Leeds, UK, one of the authors of the work.

For the first two billion years of Earth’s history, there was no oxygen in the air. That changed with the Great Oxidation Event around 2.4 billion years ago, when low levels of oxygen first appeared. This has often been attributed to the evolution of photosynthetic bacteria that release oxygen as a waste product.

Oxygen levels then rose twice more: once between 800 and 540 million years ago, and again 450-400 million years ago.