Which expression is equivalent to $3^5$?

$3 \times 3 \times 3 \times 3 \times 3$

In the expression $9^4$, what role does the number 4 play?

It is the base, the number being multiplied.

It is the product of 9 multiplied by 4.

It is the exponent, showing how many times to multiply the base by itself.

It is the sum, showing how many times to add the base to itself.