Final answer:
A 4pz orbital in a many-electron atom is degenerate with a 4px orbital, because both are p orbitals in the same principal energy level and thus have the same energy.
Step-by-step explanation:
The question asks which orbital is degenerate with a 4pz orbital in a many-electron atom. Degeneracy in this context refers to different orbitals that have the same energy level. All p orbitals within the same principal energy level (n) are degenerate with one another. This means that 4px, 4py, and 4pz orbitals have the same energy and are all degenerate.
As for the d orbitals, they are also degenerate within the same energy level, but they do not show degeneracy with p orbitals of the same principal quantum number (n). Therefore, the answer to the question is the 4px orbital, since it is in the same p subshell as the 4pz orbital.