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: Toxic actions of flurazepam ( FZP ) were studied in cats , mice and rats .
### Output Text:
Toxic actions of <span class="chemical">flurazepam</span> ( <span class="chemical">FZP</span> ) were studied in cats , mice and rats . 