You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: NATURE 
Clue: Like a tree, you can tell the age of a fish by counting these on its scales
rings

Category: BIRDS 
Clue: The willow ptarmigan, which makes its home in Arctic areas, is this state's official bird
alaska

Category: THE ELEMENTS 
Clue: Sand is composed largely of oxygen & this element, atomic number 14

silicon