The Minimum Amount of Oxygen in the Air Required for a Human

question 13

Essay

The minimum amount of oxygen in the air required for a human to survive (unaided) is around 16 percent of the current abundance in Earth's atmosphere.Using the figure below, what is the earliest time in Earth's history that a human could breathe unaided?

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Definitions:

Contractual System

A method of organization involving formal agreements between parties that specify the roles, responsibilities, and conditions of a business relationship.

Independent Retailer

An independent retailer is a business that is privately owned and operated, not part of a larger chain or franchise, offering a range of products or services to its customers.

Retail Ownership

The possession and control of a retail business, which involves selling goods directly to consumers.

Aeon

In various mythologies, a vast, indefinite period of time, often used to describe an age or era of the universe.