Earth is the only planet know to have

It is the only planet we know of that sustains life

Explanation: Thos is because we are in the goldilocks zone of our solar system, which is the region where the temperature is not too hot or too cold. It also has an atmosphere containing carbon, nitrogen, oxygen, and ozone which are gases that are necessary for life to bloom. A smaller, but important, reason is the fact that earth has a magnetic field. This shields us from harmful solar radiation that blasts off from the sun. Earth also has a moon, which controls the tides and causes the waves to break, mixing up the chemicals in the water. This combination of reasons is why Earth is the only known planet to sustain life