Answer:
1. It may also have a thick atmosphere with clouds covering most of its surface. ... It's very unlikely to be the same mix of oxygen and nitrogen as the Earth's atmosphere though. Kepler-452b may not be exactly like the Earth, but it's probably the most Earth-like planet that astronomers have found so far.
2. The mountains discovered on Pluto during the New Horizons spacecraft's flyby of the dwarf planet in 2015 are covered by a blanket of methane ice, creating bright deposits strikingly like the snow-capped mountain chains found on Earth.
3. When the solar system settled into its current layout about 4.5 billion years ago, Mars formed when gravity pulled swirling gas and dust in to become the fourth planet from the Sun. Mars is about half the size of Earth, and like its fellow terrestrial planets, it has a central core, a rocky mantle, and a solid crust.