Choose the word which is different from the rest.

The answer is Earth.

Mercury, Mars, Jupiter, and Neptune are all gas giants. Earth is a terrestrial planet.

Gas giants are large planets that are made mostly of gas. They have a thick atmosphere and a small solid core. Jupiter, Saturn, Uranus, and Neptune are all gas giants.

Terrestrial planets are smaller planets that are made mostly of rock. They have a thin atmosphere and a large solid core. Mercury, Venus, Earth, and Mars are all terrestrial planets.

Earth is the only planet in our solar system that is known to support life. It has a moderate climate, liquid water, and an atmosphere that is breathable for humans.