Answer
z
Work Step by Step
We are given the expression $yz^{5}$.
Recall that an exponential expression consists of a factor, known as the base, and an exponent. The number of times that the base is multiplied is indicated by the value of the exponent.
Therefore, z is the base of the exponent 5.
Multiplied out, $yz^{5}=y(z\times z\times z\times z\times z)$