Final answer:
The cross-section of skin that separates the epidermis and dermis determines the form and pattern of fingerprint ridges. Fingerprints form where the cells of the stratum basale meet the papillae of the papillary layer in the dermis.
Step-by-step explanation:
The cross-section of skin that separates the epidermis and the dermis is responsible for determining the form and pattern of fingerprint ridges. In a growing fetus, fingerprints form where the cells of the stratum basale meet the papillae of the papillary layer in the dermis. The papillary layer, located in the upper layer of the dermis, contains fingerlike projections called papillae that extend into the epidermis, creating the unique ridges that form fingerprints.