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: Forty - eight hr of REMD increased apomorphine - induced aggressiveness , and reduced ( immediately after completing of REMD ) or increased ( 96 hr after completing of REMD ) quipazine - induced head twitches .
### Output Text:
Forty - eight hr of REMD increased <span class="chemical">apomorphine</span> - induced aggressiveness , and reduced ( immediately after completing of REMD ) or increased ( 96 hr after completing of REMD ) <span class="chemical">quipazine</span> - induced head twitches . 