To apply the Power Rule of Exponents, you multiply the exponents when raising a power to a power. The rule states that \( (a^m)^n = a^{m \cdot n} \).
In the expression \( (10^9)^7 \):
- Applying the Power Rule: \[ (10^9)^7 = 10^{9 \cdot 7} = 10^{63} \]
Therefore, the correctly used expression is \( 10^{63} \).
So, the correct response is 1063 (10 superscript 63 baseline).