Explain a topic in that field for someone who knows nothing about it. Put your explanation in writing. I work in the administration building, so I see all sorts of people every day. They can range from students to faculty to important business people.
Transactions vary from collecting checks to making deposits.
It is my responsibility to greet them cheerfully, help them with anything in my learned capacity, and wish them a good day. I also have a monetary responsibility. I am signed out a certain amount of cash to work with. At the end of the day I am expected to present the same amount. If, for any reason, some is missing then it is my duty to solve the problem.