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: Nutritional intake , measured daily in 15 animals , showed a significant reduction of food intake in the steroid - treated groups ( - 50 and - 79 % in M and T , respectively ) .
### Output Text:
Nutritional intake , measured daily in 15 animals , showed a significant reduction of food intake in the <span class="chemical">steroid</span> - treated groups ( - 50 and - 79 % in <span class="chemical">M</span> and <span class="chemical">T</span> , respectively ) . 