Sometimes a short answer question will require that you provide a numerical value for the answer along with a unit of measurement. The question will only be graded as correct if you supply a correct value as well as a corresponding unit.
When answering a question that requires a unit, you simply type in an appropriate unit abbreviation next to the value for the answer in the input box. You can answer using any of a set of available units, and OWL will automatically do a conversion when checking the correctness of your answer.
Important: You need to enter a unit abbreviation that OWL will accept. Do not just guess at a unit and its abbreviation! Make sure to look up the available units by pressing the Unit button on the menu bar.