How can organism that don't use strach grow on a starch agar plate?

Question

How can organism that don't use strach grow on a starch agar plate?

Answer 1

They live on air.

Answer 2

Well, I don't know much about this but, we live on ground and we don't eat it.

Answer 3

It's using something else in the agar as a C source, or it's "parasitizing" a colony of another species that can use starch.  Mixed colonies are a fairly common occurrence in microbiology, particularly on early plates in an isolation series, or with organisms that make pellicles or other goo.