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: On amphetamine - induced hyperactivity , THP ( 3 . 75 and 7 . 5 mg / kg i . p . ) reduced locomotor time , distance traveled and average speed ( P < 0 . 05 ) .
### Output Text:
On <span class="chemical">amphetamine</span> - induced hyperactivity , <span class="chemical">THP</span> ( 3 . 75 and 7 . 5 mg / kg i . p . ) reduced locomotor time , distance traveled and average speed ( P < 0 . 05 ) . 