There are two broad classes of explanation.
On the basis of appearance, nebulae can be divided into two broad classes: dark nebulae and bright nebulae.
Mathematics divides phenomena into two broad classes, discrete and continuous, historically corresponding to the division between arithmetic and geometry.
Nevertheless, some waves are more localized than others, and so it is useful to distinguish two broad classes.
The British army, for example, recognizes two broad classes: (1) supplies, which include all the expendables except ammunition, and (2) stores, which include ammunition and military hardware.
Supernovae may be divided into two broad classes, Type I and Type II, according to the way in which they detonate.
Populations I and II, in astronomy, two broad classes of stars and stellar assemblages defined in the early 1950s by the German-born astronomer Walter Baade.
In short, the two broad classes of radiation are unambiguously differentiated by their speed of propagation and corresponding presence or absence of rest mass.
While classification under the heading electrolyte-solution or nonelectrolyte-solution is often useful, some solutions have properties near the boundary between these two broad classes.
Homogeneous reaction, any of a class of chemical reactions that occur in a single phase (gaseous, liquid, or solid), one of two broad classes of reactions homogeneous and heterogeneous based on the physical state of the substances present.
Structures may be divided into two broad classes: the primary structures that were acquired in the genesis of a rock mass and the secondary structures that result from later deformation of the primary structures.
