These are university courses. You don't learn anything useful by having someone tell you the 'right answer' to a made-up problem. The point of the problems is to learn to think about the issues and build the skills needed to find answers. Study groups are places where students can help each other build these skills. Even in face-to-face tutorials, a good TA doesn't just tell students the answers, but helps them find their own ways to the answers.

The tests I give are all 'open book', which I define as allowing any books, notes, documents or other aids (e.g. little model chromosomes for genetics problems) but no electronics. Unfortunately this means no e-texts.

These bugs are closely related to common spore-forming terrestrial bacteria. What the researchers probably collected were stray spores (very resistant to drying and UV) just drifting around.