Final answer:
The inner planets are composed of rocks and metals and have solid surfaces, yet they exhibit varying characteristics such as atmospheric composition and geological features due to their formation histories and positions in the solar system.
Step-by-step explanation:
The inner planets, also known as terrestrial planets, are made up of rocks and metals and have solid surfaces. While they are composed of similar materials, each has unique features and characteristics.
For instance, Mercury has a very thin atmosphere and experiences extreme temperatures. Venus, although similar in size to Earth, has a thick, toxic atmosphere with intense surface heat and pressure. Earth is unique with its abundant liquid water and life-supporting atmosphere. Lastly, Mars has the largest volcano and canyon in the solar system, and while it has a thin atmosphere, it's known for massive dust storms.
The differences among the inner planets are a result of their formation histories, positions in the solar system, and geological and atmospheric evolution. These factors have affected surface temperatures, geological activity, and atmospheric presence or absence among the terrestrial planets.