Currently, two major hypotheses have been proposed, which are not mutually exclusive.

Although the gross histological features of AD in the brain are well characterized, three major hypotheses have been advanced regarding the primary cause.

The Keynesian consumption function was based on two major hypotheses.

There seem to be two major hypotheses.

Three major hypotheses for the molecular nature of this plasticity have been well-studied, and none are required to be the exclusive mechanism:

There are two major hypotheses that attempt to explain variation in clutch size among cavity-nesting bird species.

There are two major hypotheses that depend solely on the spatial and areal characteristics of the tropics.

There are three major hypotheses as to how they evolved their stubby fins (proto-limbs).

There are two major hypotheses for the ascent of magma through the crust:

There are two major hypotheses regarding the origins of the avoirdupois system.