23691
While our knowledge about the genes is clearly better for T1D than for T2D given the strong contribution of variation in the HLA region to the risk of T1D , the opposite is the case for T2D , where our knowledge about the environmental triggers ( obesity , lack of exercise ) is much better than the understanding of the underlying genetic causes .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None