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: Response rates were 87 . 3 % ( 89 / 102 ) in the T + A group and 69 . 3 % ( 70 / 101 ) in the A group ( P < 0 . 05 ) .
### Output Text:
Response rates were 87 . 3 % ( 89 / 102 ) in the T + A group and 69 . 3 % ( 70 / 101 ) in the A group ( P < 0 . 05 ) . 