The level of oxygen in the form of O₂ in the Earth's atmosphere ________________. A)has not changed substantially in the past 450 million years B)is drastically decreasing due to pollution C)is no different than it was 4.6 billion years ago D)is drastically increasing due to growth of new bacterial strains E)cannot change because Earth is a closed system

Question

Quizplus · Accepted Answer

The level of oxygen in the Earth's atmosphere has not changed substantially in the past 450 million years. This period of time is known as the Phanerozoic Eon during which oxygen levels have remained relatively stable, allowing for the development and diversification of complex life forms. While there have been fluctuations in oxygen levels over the course of Earth's history, the current level of oxygen is sufficient to support life and shows no evidence of drastic decrease or increase.

The Level of Oxygen in the Form of O2 in the Earth's

The Level of Oxygen in the Form of O₂ in the Earth's