"you see a rock on campus. it is a big white boulder, and you look closer. you see a salt and pepper appearance. you look closer. you see crystals that are about as big as your fingernail. they interlock together, as though they grew in place as magma slowly cooled. what general type of rock are you looking at?

igneous rock

Explanation:

There are three main kinds of rocks, sedimentary, metamorphic and igneous.

The igneous rocks are the ones that formed from a hot source like magma inside the soil, as it gets to the surface of the Earth it goes cooling. If it cools almost in the surface of the Earth then is consider a plutonic rock.

Plutonic Rocks have a big quantity of minerals, since they cool under a big pressure, these minerals get together forming a solid rock.

By passing the time the granites of minerals can be easily seen at naked eye, like the characteristics of these sample.

answer; round wood logs, building materials like (plywood),also pulp and paper products;

the precambrian aged rocks could be found in australia. australia is a region that has a lot of ancient civilization history from million years ago. in this region, there are a lot of recognizable fossils buried in its land which is considered a precambrian-aged rocks