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: Acute normal tissue toxicities ( i . e . , leukopenia and thrombocytopenia ) and late normal tissue toxicities ( i . e . , myocardial and kidney injury ) were evaluated by functional / physiological assays and by morphological techniques .
### Output Text:
Acute normal tissue toxicities ( i . e . , leukopenia and thrombocytopenia ) and late normal tissue toxicities ( i . e . , myocardial and kidney injury ) were evaluated by functional / physiological assays and by morphological techniques . 