Fingernails Are Made of This Substance
This page is the CodyCross answer for the clue below from All Things Water, Group 1284, Puzzle 1 (Lochs and Basins).
Question is: Fingernails Are Made of This Substance
and the answer is: KERATIN
Word Meaning:
KERATIN — (biochemistry) The protein of which hair and nails are composed.
Definitions from Wiktionary.