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: The hepatocellular pattern of damage was the most common ( 58 % ) , was inversely correlated with age ( P < . 0001 ) , and had the worst outcome ( Cox regression , P < . 034 ) .
### Output Text:
The hepatocellular pattern of damage was the most common ( 58 % ) , was inversely correlated with age ( P < . 0001 ) , and had the worst outcome ( Cox regression , P < . 034 ) . 