Cell Lab is currently being developed so it receives updates now and then. Sometimes I add new challenges/rename challenges and that makes this forum a bit confusing. Please write the full text of the challenge as topic, eg. "7: Macrophages III" and also write the app version seen in the about page of Cell Lab in your first comment to minimize confusion.
If you find hints in this forum that make no sense for your challenge, it is probably because the numbers have changed since it was written so then look at the other/newer comments and if nothing matches, make a new topic.
Sorry about the mess

Petter