Resume
Basically they need your experience information, hence they typically ask for your resume. But, the resume is not sent to INS. They use resume to fill the ETA 750 A/B form (This is the paperwork needed for filing labor). Even in substituted labor situations like us, they will fill the ETA 750 forms but they dont file the forms with the labor department. They need your resume to fill these forms.
They send the I-140 petition, our filled, uncertified forms (Uncertified: Because they were never sent to labor department) along with the original approved labor petition to INS for filing I-140. This is the typical process for substituted labor.
Hope it helps...