[Aligula did a rather good job with her questionnaire. There's one that gets Naoto's attention, may as well say it to everyone...]

What are the most suspicious spot we have seen? Anything that looks abnormal or strange may be a valuable clue.

For example, Mozu-san told me the trees in the Greenhouse are rather unusual. It seems the roots are oddly weak, for a tree. I examined them myself, but they do seem to be trees...

[...]

I don't know if it's no more than a mere quirk of the greenhouse, but I thought it would be good to mention it.