Consistency as applied to cohesive soils is an indicator of its shear strength.

Explanation:
Consistency refers to the ability of a cohesive soil to resist deformation under stress. It is an important property of cohesive soils as it directly affects their shear strength, which is the ability of a soil to resist sliding along internal planes.

Cohesive soils, such as clay, have cohesive forces between their particles due to the presence of water films. These cohesive forces give the soil its strength and plasticity. The consistency of cohesive soils can vary depending on their moisture content, density, and other factors.

Moisture Content:
The moisture content of cohesive soils plays a significant role in determining their consistency. As the moisture content increases, the soil becomes more plastic and softer, leading to a decrease in its shear strength. Conversely, as the moisture content decreases, the soil becomes stiffer, resulting in an increase in its shear strength.

Density:
The density of cohesive soils also affects their consistency. Generally, denser soils have higher shear strength and are more resistant to deformation. However, the relationship between density and consistency can be complex, as factors such as compaction methods and soil structure also influence the soil's behavior.

Shear Strength:
Consistency is primarily an indicator of the shear strength of cohesive soils. Shear strength is the ability of a soil to resist shear stresses, or the force acting parallel to a potential sliding plane within the soil. It is an essential parameter in geotechnical engineering, as it determines the stability of slopes, retaining walls, and foundations.

Porosity:
Porosity refers to the amount of void space within a soil. While it can indirectly affect the consistency of cohesive soils by influencing their moisture content and density, it is not a direct indicator of consistency. Porosity primarily impacts the permeability and compressibility of soils.

In conclusion, consistency is a property of cohesive soils that is closely related to their shear strength. It is influenced by factors such as moisture content and density, which in turn affect the soil's ability to resist deformation and shear stresses.