An element that increases creep strength in metal is:

Molybdenum is known for its ability to enhance the creep strength of metals, especially at high temperatures. Creep strength refers to a material's ability to resist deformation under mechanical stress over prolonged periods, particularly in high-temperature environments. Molybdenum achieves this by forming solid solutions and reinforcing structures within the metal, which helps to stabilize the material at elevated temperatures.

Other elements, while they have various properties and benefits (such as improving toughness or resistance to oxidation), do not have the same specific impact on increasing creep strength as molybdenum does. For instance, manganese can improve hardness and strength, vanadium can enhance strength and wear resistance, and nickel can improve ductility and toughness, but none match molybdenum's effectiveness in specifically addressing creep behavior in metals. This characteristic makes molybdenum a critical addition in alloys used in high-temperature applications like gas turbines and nuclear reactors.