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: Renal angiotensin II receptor type 2 ( AT2R ) gene expression in adult offspring was reduced by PCE , whereas the renal angiotensin II receptor type 1a ( AT1aR ) / AT2R expression ratio was increased .
### Output Text:
Renal <span class="chemical">angiotensin II</span> receptor type 2 ( AT2R ) gene expression in adult offspring was reduced by PCE , whereas the renal <span class="chemical">angiotensin II</span> receptor type 1a ( AT1aR ) / AT2R expression ratio was increased . 