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: A minority of anionic sites were scattered throughout the lamina densa and lamina rara interna , and were significantly smaller than those in the lamina rara externa of the glomerular basement membrane ( p < 0 . 001 and p < 0 . 01 for diabetic and control rats , respectively ) .
### Output Text:
A minority of anionic sites were scattered throughout the lamina densa and lamina rara interna , and were significantly smaller than those in the lamina rara externa of the glomerular basement membrane ( p < 0 . 001 and p < 0 . 01 for diabetic and control rats , respectively ) . 