What is the third planet from the Sun?

The third planet from the Sun is Earth. The order of the planets in our solar system, starting from the Sun, is Mercury, Venus, Earth, and then Mars. This arrangement is based on their average distance from the Sun. Earth is unique in this position as it is the only known planet that supports life, featuring the right conditions such as liquid water, a suitable atmosphere, and a range of temperatures that allow for diverse ecosystems. The recognition of Earth's place in the solar system emphasizes its importance as a home for all known life and highlights the factors that contribute to its habitability compared to its planetary neighbors.