Why is granite an intrusive igneous rock?

Answer 1

It is igneous because it crystallizes out of cooling magma.

It is intrusive because it can only form deep below ground. The magma cools down very slowly when it is deep below ground and this allows the different minerals that make up granite to grow crystals to sizes big enough that you can see them with the naked eye. If it had cooled fast, like if it was at the surface, then the individual crystals making it up would be super tiny and the resulting rock could not be classified as granite.

Answer 2

Granite is an intrusive igneous rock because it forms beneath the Earth's surface from the slow cooling and solidification of magma. This slow cooling allows large mineral crystals to form, giving granite its characteristic coarse-grained texture.