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: These results suggest that edaravone suppresses streptomycin - induced vestibulotoxicity .
### Output Text:
These results suggest that <span class="chemical">edaravone</span> suppresses <span class="chemical">streptomycin</span> - induced vestibulotoxicity . 