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: SCIENCE & NATURE 
Clue: Developed by astronomer A.E. Douglass, dendrochronology determines age in this way
counting tree rings

Category: RELIGION 
Clue: Some 3 million pilgrims visit this small French town annually
lourdes

Category: HEADS OF STATE 
Clue: Shimon Peres, elected by the Knesset as the 9th president in 2007

israel