Okay so, when we reverted a buncha stuff in e3d196f, it was in response
to a bug where item modeling data was getting deleted. And I was tired,
and just took a big simple hammer to it of reverting all the modeling
refactors.
Here, we reintroduce *some* of them: the biology ones before the item
bug. And tests still pass, and in fact I can un-pending some of them!
I might also try to reapply the change where we extract it all into a
new file, but without the item parts.
```shell
git cherry-pick --no-commit 13ceec8fcc
git cherry-pick --no-commit f81415d327
git cherry-pick --no-commit c03e7446e3
git cherry-pick --no-commit 52ca41dbff
```
Emi Matchu
54b25ef08e
