Final answer:
In the density equation (d = m/V), mass (m) is the basic quantity as it is a fundamental measure of the amount of matter.
Step-by-step explanation:
The quantity considered a basic quantity in the density equation (d = m/V) is mass (m). Mass is a fundamental physical quantity representing the amount of matter within an object, whereas volume (V) is a derived quantity expressing the space that a substance or object occupies. Density (d) itself is an intensive property that is calculated by dividing the mass of a substance by its volume.