What is not a factor that affects the viscosity of magma?

Age

Depth

Explanation:

Viscosity is referred to as a measure of a material's resistance to flow

Rise in temperature or heat, burial, exposure to existing magmas, dissolved gases, exposure to mantle plumes, decreasing pressure, and high water content, crystal composition are factors that affect the viscosity of magma;

However, age and depth are two of the factors that do not affect the viscosity of magma/lava