To simplify the expression \( 3^2 \cdot 3^{-5} \), we can use the property of exponents which states that \( a^m \cdot a^n = a^{m+n} \).
In this case:
\[ 3^2 \cdot 3^{-5} = 3^{2 + (-5)} = 3^{-3} \]
Now, we can express \( 3^{-3} \) in terms of a fraction:
\[ 3^{-3} = \frac{1}{3^3} \]
Thus, the expression \( 3^2 \cdot 3^{-5} \) simplifies to \( \frac{1}{3^3} \).
Based on the answer choices, the equivalent expression is:
fraction \( 1 \) over \( 3 \) to the power \( 3 \).