Which variable is NOT listed as affecting a material's resistance to gravity and fire degradation?

The variable that does not influence a material's resistance to gravity and fire degradation is related to the economic aspect of construction rather than the material properties themselves. The cost of construction reflects financial decisions, project budgeting, and affordability but does not directly affect the physical and mechanical characteristics of materials regarding how they respond to gravitational forces and their performance when exposed to fire.

In contrast, elements such as material type and mass play a critical role in determining a material's structural integrity and its ability to withstand weight and pressure. The surface-to-mass ratio also significantly impacts how materials interact with heat and fire; materials with a larger surface area may heat up more quickly due to increased exposure to flames, thus influencing their degradation. The age of the building is another important factor; older materials may be more susceptible to wear and degradation, impacting their resistance to gravity and fire due to potential deterioration over time.

Overall, while the cost of construction is an essential consideration during the building process, it is not a variable that affects the physical resistance of materials in the context of gravity and fire degradation.