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The ones we know of - and can get a decent albedo reading and spectroscopic analysis of - seem to have rocky cores covered with ices, by and large, but there is still much more not known about the minor planets than is known. Also note that this answer assumes by the "minor planets" you are talking primarily about the trans-Neptunian objects. If by "minor planets" you meant the larger asteroids of the asteroid belt, they are rocks, to keep it simple.
What else can I help you with?
What are Earth and the other planets closest to the sun are made mostly?
Earth and the other planets are mostly made of rock.
Why are the smallest planets the densest?
because they are made of mostly metal and rock while the bigger planets are mostly made of gas
What are the outermost planets mostly made of?
Ices.
Are the inner planets large planets made up of mostly gas?
No, those are the outer planets.
What are the gassy planets made of?
They are made mostly of hydrogen and helium.
What are the giant outer planets made mostly made out of?
Gases
What are the inner planet mostly made of?
The inner planets are mostly made of iron and rock.
What are the giant outer planets mostly made of?
Rocks
What are the gassy planets?
They are made mostly of hydrogen and helium.
Which planets mostly made of atmosphere?
venus and earth.
How are the inner planets different from the outer planets?
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.
What is a inner planer?
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
