1. C: large, well-defined crystals
2. C: magma cools and solidifies
3. B. Intrusive
Crystals form when molecules collect into an ordered structure. In order for this to happen, the molecules need to be free to move. So if the cooling happens suddenly, the molecules go from a liquid to a solid rapidly before they have a chance to form large crystals. So fast cooling = none to small crystals. Slow cooling = large crystals. With that in mind, let's look at the questions and options.
1. An igneous rock that forms from long, slow cooling is characterized by.Since we're talking slow, this means large crystals, which is option "C: large, well-defined crystals"
2. Igneous rocks form when.
Igneous rock is one of the 3 major types of rock. Since igneous comes from the Latin word ignis meaning fire, igneous rocks are those rocks that come from the cooling of molten material such as lava or magma. This matches option "C: magma cools and solidifies"
3. An igneous rock displays coarse-sized grains that can easily be seen with the naked eyes. The rock is most likely
Since the grains are easily seen, this indicates that the rock cooled reasonably slowly. Of the available options, extrusive doesn't work since extrusive rock occurs when magma reaches the surface and cools rapidly, so you have small crystals. Intrusive does work since in that case magma cools slowly and therefore has larger crystals. And since both extrusive and intrusive rocks can be considered volcanic, volcanic is just too general a term since intrusive describes the rock more accurately. Therefore the answer is "B. Intrusive"
