Planarians (guess)

Planarians are flatworms that can be used to study the effect of different substances on the nervous system. In this remote laboratory, you can choose the solution into which to place the planarian worms. The solutions are aqueous and have different exitatory or inhibitory substances, with different concentrations, dissolved into them.

In this version of the laboratory, the names of the substances are not displayed. The challenge can thus be to determine which substance is which, by measuring the activity level of the planarians in each unknown substance.