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: We studied the effects of terbutaline on microglial activation in different brain regions and behavioral outcomes in developing rats .
### Output Text:
We studied the effects of <span class="chemical">terbutaline</span> on microglial activation in different brain regions and behavioral outcomes in developing rats . 