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 animals that had experienced cyclic sucrose and chow were hyperactive in response to amphetamine compared with four control groups ( ad libitum 10 % sucrose and chow followed by amphetamine injection , cyclic chow followed by amphetamine injection , ad libitum chow with amphetamine , or cyclic 10 % sucrose and chow with a saline injection ) .
### Output Text:
The animals that had experienced cyclic <span class="chemical">sucrose</span> and chow were hyperactive in response to <span class="chemical">amphetamine</span> compared with four control groups ( ad libitum 10 % <span class="chemical">sucrose</span> and chow followed by <span class="chemical">amphetamine</span> injection , cyclic chow followed by <span class="chemical">amphetamine</span> injection , ad libitum chow with <span class="chemical">amphetamine</span> , or cyclic 10 % <span class="chemical">sucrose</span> and chow with a saline injection ) . 