What scientific term describes the amount of a material present per unit of volume?

The scientific term that describes the amount of a material present per unit of volume is density. Density is defined as mass per unit volume, which can be mathematically expressed as D = m/V, where D represents density, m is mass, and V is volume. This concept is crucial in various scientific and engineering disciplines as it helps to identify how much matter is packed into a given space.

In practical applications, understanding density is vital for tasks such as determining whether an object will float or sink in a fluid, as well as for solving problems related to material properties in chemistry and physics. The correct identification of density allows scientists and engineers to predict how substances will behave in different conditions.

Other options relate to different concepts: mass refers to the quantity of matter in an object, volume is the amount of three-dimensional space an object occupies, and concentration refers to the amount of a substance within a defined space or solution but does not inherently factor volume like density does.