Basalt generally includes which one of the following?

Basalt is a volcanic rock that is commonly formed from the rapid cooling of lava that is rich in magnesium and iron. One of its notable characteristics is its composition, which often includes small green crystals of olivine. Olivine is a silicate mineral that is typically found in mafic rocks, such as basalt, and contributes to its overall texture and mineralogical content.

In the context of basalt, these small green crystals of olivine are an important identifying feature because they reflect the rock's origin from a high-temperature, low-viscosity lava that solidifies relatively quickly. The presence of olivine gives basalt its characteristic color and contributes to its density.

The other options do not accurately represent the common characteristics of basalt. For example, large quartz crystals are typically associated with more silicic and less mafic rocks, while pumice is a light, porous volcanic rock that forms from the rapid cooling of gas-rich lava, and high levels of iron, while present in basalt, do not specifically define the typical features most associated with this rock type.