Which phrases describe an extrusive rock? check all that apply. fine texture cooled slowly small crystal size found deep underground different, easily observed minerals

The correct answers are:

- fine texture;

- small crystal size;

The extrusive rocks are type of rocks that form on the surface of the Earth, be in water or on land. They form from the magma that cools of very quickly on the surface. Because of the quick cooling, this type of rocks have very small crystals, or none at all, as they do not have the time and the conditions to form. Usually they are also finely-grained rocks, which is a often a good indicator that it is an extrusive rock when observed.

This types of rocks can mostly be found close to volcanoes, both active and non-active, as well as the mid-ocean ridges.

some scientists like gregory adcock agree with thorne's theory of regional continuity.

others, like chris stringer and ian tattersall, believe thorne's results may be contaminated or misinterpreted.