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: In behavioral tests , animals treated with terbutaline on PN 2 to 5 showed consistent patterns of hyper - reactivity to novelty and aversive stimuli when assessed in a novel open field , as well as in the acoustic startle response test .
### Output Text:
In behavioral tests , animals treated with <span class="chemical">terbutaline</span> on PN 2 to 5 showed consistent patterns of hyper - reactivity to novelty and aversive stimuli when assessed in a novel open field , as well as in the acoustic startle response test . 