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 genes presented represent ( 1 ) greater than 1 . 5 - fold change in either direction and ( 2 ) the p value is less than 0 . 05 for the comparison being made .
### Output Text:
The genes presented represent ( 1 ) greater than 1 . 5 - fold change in either direction and ( 2 ) the p value is less than 0 . 05 for the comparison being made . 