Earth’s Oxygen-Rich Atmosphere
As far as we know, Earth is the only planet that supports life. Earth’s atmosphere has three main features that make it unique among the planets and that make life on Earth possible. These features are significant oxygen levels, a protective ozone layer, and a moderate greenhouse effect.
First, we will look at Earth’s oxygen-rich atmosphere. Oxygen is an essential component of our red blood cells and is circulated throughout our bodies, allowing for metabolic function. Earth’s atmosphere is nearly 21% oxygen, just the right amount to support life. If Earth had any less, there would not be sufficient oxygen to support animal metabolism. On the other hand, if Earth had just five percent more oxygen, then life could not exist because organic materials would burn too easily, wiping them out completely.
