Use "subtopic" in a sentence

1. subtopic, but how you select this subtopic and how you determine whether it is profitable

2. So for each term that is a "subtopic" (you have to use your judgement here) and has a lot of searches, you should run it again through the Keyword Selector tool and create a list for

3. Subtopic: Hemoglobinopathies and Thalassemias