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: LF prevented body weight loss and significantly reduced the elevated plasma H2O2 and increased FRAP values .
### Output Text:
LF prevented body weight loss and significantly reduced the elevated plasma <span class="chemical">H2O2</span> and increased FRAP values . 