Final answer:
The sigma factor in prokaryotes helps RNA polymerase recognize and bind to the promoter sequence before being ejected.
Step-by-step explanation:
In prokaryotes, the sigma factor plays a crucial role in transcription initiation. It binds to the RNA polymerase and helps it recognize and bind to the promoter sequence of a gene. Once the RNA polymerase is properly aligned with the promoter, the sigma factor is ejected and the transcription process begins. Therefore, the statement is True.