11354
Substantial evidence shows that H ( 2 ) S is involved in aging by inhibiting free - radical reactions , activating SIRT1 , and probably interacting with the age - related gene Klotho .
 H ( 2 ) S
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 H ( 2 ) S