Task: Text Categorization
Input (English): Imetelstat, a potential new cancer therapy agent, works by targeting the enzyme that repairs these   structures. Blackburn, Greider, and Szostak received the 2009 Nobel Prize for determining the role of  these structures, which typically adopt a G-quadruplex shape. The shortening of these structures   explains the Hayflick limit to cell division and is the basis for the cellular theory of aging, and that  shortening of these structures can lead to cell senescence or apoptosis. Consisting of thousands of  TTAGGG repeats in humans, name these end sequences of chromosomes that prevent genes from  being lost during DNA replication.
Output (English): Science