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: Our findings showed that pubertal BPA exposure increased anxiety - like behavior , which may be associated with decreased AChE activity of the hippocampus in adult male mice .
### Output Text:
Our findings showed that pubertal <span class="chemical">BPA</span> exposure increased anxiety - like behavior , which may be associated with decreased AChE activity of the hippocampus in adult male mice . 