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: From the above result it is suggested that the pressor response to i . c . carbachol ortral and peripheral adrenergic mechanisms , and that the sympathetic trunk is the main pathway .
### Output Text:
From the above result it is suggested that the pressor response to i . c . <span class="chemical">carbachol</span> ortral and peripheral adrenergic mechanisms , and that the sympathetic trunk is the main pathway . 