“I rarely see a real variable cost or a truly fixed cost.” What did she mean?

(Chapter 1 Discussion Question 9(a)) Controller, Judy Koch, in a recent speech said, “I rarely see a real variable cost or a truly fixed cost.”  What did she mean?  Include in your response an explanation of the difference in behavior of variable and fixed cost, including an example to illustrate your explanation. Your initial post should be 200 to 250 words.