The Earth is classified as a terrestrial planet. Terrestrial planets are characterized by their solid, rocky surfaces and are composed mainly of silicate rocks and metals. This classification includes Mercury, Venus, Earth, and Mars, all of which have distinct atmospheres and geological features. Earth, in particular, is unique with its liquid water, diverse ecosystems, and atmosphere rich in oxygen, making it the only known planet to support life. The classification of Earth as a terrestrial planet highlights its physical properties and significance in the study of planetary science.