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: Deoxycholic acid conjugation , transport capacity , and metabolism were compared in control and ethinyl estradiol - treated rats .
### Output Text:
<span class="chemical">Deoxycholic acid</span> conjugation , transport capacity , and metabolism were compared in control and <span class="chemical">ethinyl estradiol</span> - treated rats . 