What is one way the gas giants differ from the terrestrial planets

what is one way the gas giants differ from the terrestrial planets?

Planets that are largely comprised of rock, such as rocky or terrestrial planets, are not like gas giants. Unlike rocky planets, gas giants lack a clearly defined surface there is no obvious line separating the atmosphere from the surface. The atmospheres of the gas giants are primarily hydrogen and helium.

allowed for the prediction of the properties of missing elements.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.