In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: A 34 . 4 % ( 12 / 27 ) of SVR + biological response in group A was higher than 10 % ( 1 / 10 ) in group B ( P = 0 . 051 ) , with slight significance .
### Output Text:
A 34 . 4 % ( 12 / 27 ) of SVR + biological response in group A was higher than 10 % ( 1 / 10 ) in group B ( P = 0 . 051 ) , with slight significance . 