| Answer | Crossword Clue |
|---|---|
| IGLU | It has cold walls (var.) |
| nephridium | (in many invertebrate animals) A tubule open to the exterior that acts as an organ of excretion or osmoregulation. It typically has ciliated or flagellated cells and absorptive walls |
| nephridia | (in many invertebrate animals) A tubule open to the exterior that acts as an organ of excretion or osmoregulation. It typically has ciliated or flagellated cells and absorptive walls |
