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: Results from our behavioral phenotyping indicated that anxiety - like behavior was increased in mice exposed to BPA .
### Output Text:
Results from our behavioral phenotyping indicated that anxiety - like behavior was increased in mice exposed to <span class="chemical">BPA</span> . 