Because it has sufficient gravity and a strong magnetosphere.
Gravity
Planet Earth - about 80%.
Gases in the Earth's atmosphere stay close to the surface due to the force of gravity acting on them. Gravity pulls the gases towards the center of the planet, keeping them from escaping into space. The mass of the Earth is sufficient to maintain an atmosphere that surrounds the planet.
No. No. The only planet n contact with Earth's atmosphere is Earth itself.
Earth is the only known planet with an oxygenated atmosphere.
The Earth has an atmosphere because it has the gravity necessary to keep the gases from floating off into space. The more mass a planet has, the more gravity it has, and the more gravity it has, the thicker an atmosphere it can sustain.
The earth is the largest planet in our atmosphere. Jupiter is the largest planet in out solar system.
The atmosphere helps maintain the right temperature on Earth by trapping heat from the sun through greenhouse gases such as carbon dioxide and water vapor. These gases absorb and emit infrared radiation, warming the planet. Without the atmosphere's insulation, Earth's surface would be much colder.
No. There is not another planet inside Earth.
We are adapted to breathing and living in Earth's atmosphere. A planet would need to have an atmosphere similar to that of Earth for people to find it livable.
Earth
It is none other than our own planet Earth, which has nitrogen and oxygen in its atmosphere.