The correct answer is: $0.001$
Explanation
Negative exponents mean “reciprocal of the positive exponent.” So $10^{-3}$ means one divided by $10^3$.
Steps:
- Write the reciprocal form: $$10^{-3} = \frac{1}{10^3}$$
- Evaluate the positive power: $$10^3 = 1000$$
- Compute the fraction: $$\frac{1}{1000} = 0.001$$
Therefore, $10^{-3} = 0.001$.