Final answer:
Segmentation is the step in the STP process that develops descriptions of different segments and helps firms understand customer profiles.
Step-by-step explanation:
The step in the STP process that develops descriptions of the different segments, which helps firms better understand the customer profiles in each segment is Segmentation.
Segmentation involves dividing the market into distinct groups based on similar characteristics, such as demographics, psychographics, or behaviors. This step allows firms to identify and understand their target audience and tailor their marketing strategies to meet the specific needs and preferences of each segment.