How does crystal size compare in extrusive vs. intrusive rock? explain the cause of this difference.

The major visible difference between the two are crystal size, intrusive rocks have a larger crystal/grain texture due to the slow cooling of magma below the earth surface which encourages the growth of larger crystals, while extrusive rocks, because of the rapid cooling at/above the earth's surface does the opposite.

Iguess i would say diagrams would be most difficult subject too correct