Final answer:
The answer is A. Combinations of minerals and/or once-living things.Rocks are combinations of minerals and/or once-living materials, with granite as an example composed of quartz, feldspar, and mica.
Step-by-step explanation:
Rocks are made of minerals and can consist of various combinations of minerals or a single mineral. Minerals themselves are naturally occurring, inorganic solids with a definite chemical composition and a crystalline structure. Rocks are classified into three basic types: igneous, sedimentary, and metamorphic. For example, granite is composed of minerals such as quartz, feldspar, and mica that are interlocked in a solid matrix. However, rocks can also include materials from once-living organisms, such as the calcite in limestone, which is often composed of accumulated marine organism remains.
Minerals are the basic building blocks of rocks and can be difficult to identify. There are three basic types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form when magma or lava cools, sedimentary rocks form from broken pieces of other rocks, and metamorphic rocks are altered by heat and pressure.