What gas made up the largest portion of earth's atmosphere for most of earth's history

Gases in Earth's Atmosphere. Nitrogen and Oxygen are by far the most common. Dry air is composed of about 78% Nitrogen (N2) and about 21% Oxygen (O2). Argon, Carbon Dioxide (CO2), and many other gases are also present in much lower amounts; each makes up less than 1% of the atmosphere's mixture of gases.

So therefore Oxygen is the gas that makes up the largest portion of the Earths Atmosphere.

answer

crater lake was formed when mount mazama produced a large eruption and collapsed to form a caldera, which then filled with water forming a lake.

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

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