Measurements
The length of a worker ant is 8.32x10^(-3) feet and the length of the queen ant is 1.9x10^(-2) feet.
We are required to find the difference in the lengths of both ants:

To calculate the difference, we must express both numbers with the same exponent. Let's use the exponent -2 as the common one:

This difference is expressed in feet. The correct choice is 1.068 x 10^-2
This number is too small to manage. For this situation, a smaller unit of measure should have been used. From the available options, the only one that is smaller than feet is inches.
Answer: Inches