The given expression 0.00001 can be rewritten as 10⁻⁵. This is because 0.00001 is equivalent to dividing 1 by 100,000, which can be expressed as 1/10⁵. In scientific notation, 10⁻⁵ represents a number that is 10 raised to the power of -5, which is the same as dividing 1 by 10⁵. Therefore, the correct answer is 10⁻⁵.