The Earth approx. 80% nitrogen 20 % oxygen
mainly because they are not shown by the sun.The sun gives heat,oxygen,and more.
Earth and the other planets are mostly made of rock.
because they are made of mostly metal and rock while the bigger planets are mostly made of gas
Earth's atmosphere is mostly made up of nitrogen and oxygen; but the planet itself is more than just its atmosphere - overall Earth, like other terrestrial planets, is mostly made from rock (silicates) with a nickel-iron core. (By comparison, overall the outer gas planets are mostly made from hydrogen and helium.) By relative abundance, oxygen is also the most common element in the Earth's crust.
Ices.
No, those are the outer planets.
They are made mostly of hydrogen and helium.
Gases
The inner planets are mostly made of iron and rock.
The inner planets Mercury, Venus, Earth and Mars are small, heavy and mostly made of rock. The outer planets Jupiter, Saturn, Uranus and Neptune are huge, light and mostly made of gas.
An inner planet is mostly made of iron and has more mass than outer planets, outer planets are mostly made of gasses, makeing them have less mass. The inner planets are the planets between the asteroid belt and the sun
Rocks