43691
After the discovery of the hydrogen bonded A : T and C : G pairs , Watson and Crick soon had their anti-parallel , double helical model of DNA , with the hydrogen bonds at the core of the helix providing a way to " unzip " the two complementary strands for easy replication : the last key requirement for a likely model of the genetic molecule .
 person: Watson; person: Crick
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Watson, Crick 
Answer:
 person: Watson; person: Crick