Question

which layer of hair is described as the central core made of soft keratin? dermal papilla cuticle medulla cortex

Explanation:

The medulla is the central core of the hair, composed of soft keratin. The dermal papilla is part of the hair follicle's structure, not a hair layer. The cuticle is the outer protective layer of the hair, and the cortex is the main body of the hair, containing most of its pigment and structural proteins. So, the description in the question fits the medulla.

Answer:

C. Medulla