8777
We show that the surfaces of tracheal cartilage matrix are collagen - rich and surround a proteoglycan - rich core .
 GENE: collagen
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities: collagen 
Answer:
 GENE: collagen