Merkel cells found in the stratum basale of the epidermis helps Jill, who is blind, to discriminate between the textured dots.
Explanation:
Merkel cells are tactile epithelial cells also called Merkel-Ranvier cells are located at the stratum basale (base) of epidermal layer, especially around the sweat pores.
These are mechanoreceptors which functions for light-touch sensation. Light touch sensations are used by blind to read Braille, musicians playing keyboard, seamstress feeling the soft silk etc.
Blind people read through Braille dot pattern inscriptions which is a tactile writing pattern.
The Merkel cells help to discriminate the patterns of the Braille textured dots.