Final answer:
Elastic moduli relate stress to strain, thermal conductivity relates heat flux to temperature gradient, and density causes loading due to gravity.
Step-by-step explanation:
The material properties that relate stress to strain are known as the elastic moduli. There are three types of elastic moduli: Young's modulus, which relates tensile stress to strain; the bulk modulus, which relates volumetric stress to strain; and the shear modulus, which relates shear stress to strain.
The material property that relates heat flux to the temperature gradient is known as thermal conductivity. Thermal conductivity is a measure of a material's ability to conduct heat.
The material property that causes loading due to gravity is density. Density is a measure of mass per unit volume and determines the amount of force exerted by an object under the influence of gravity.