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: Control chicks were in motion an average of 33 . 67 % of the time , while coniine - treated chicks were only moving 8 . 95 % of a 5 - min interval , and no movement was observed for nicotine sulfate treated chicks .
### Output Text:
Control chicks were in motion an average of 33 . 67 % of the time , while <span class="chemical">coniine</span> - treated chicks were only moving 8 . 95 % of a 5 - min interval , and no movement was observed for <span class="chemical">nicotine</span> sulfate treated chicks . 