The only planet known to support life is Earth. Earth has the unique combination of factors necessary for life, including a suitable atmosphere, temperature range, and the presence of water in liquid form. The planet's atmosphere contains oxygen, which is vital for respiration for most living organisms, and a balanced climate that supports diverse ecosystems. Earth's magnetic field protects it from cosmic radiation, and its distance from the sun places it in the "Goldilocks zone," where conditions are "just right" for sustaining life. This remarkable set of conditions makes Earth distinct in the universe.