Ices.
The four outermost planets (Jupiter, Saturn, Uranus, Neptune) are mostly made of hydrogen and helium gas, with smaller amounts of other elements like water, ammonia, and methane. These planets are known as gas giants because of their composition and lack of a solid surface.
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
Neptune is the fourth and outermost of the gas giant planets and also has rings. Its atmosphere is mostly hydrogen and helium.
What is the reason that life is less likely on the outermost planets compared to the innermost planets
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.
Rocks
They are made mostly of hydrogen and helium.
venus and earth.