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: There were also differences between HDS and LDS for HR ( p less than 0 . 001 ) and Glu ( p less than 0 . 05 ) responses .
### Output Text:
There were also differences between HDS and LDS for HR ( p less than 0 . 001 ) and <span class="chemical">Glu</span> ( p less than 0 . 05 ) responses . 