Anatomy and Physiology

Answer:

In a strand of hair, its base is called the hair matrix, where hair growth occurs via epithelial stem cell divisions. As new hair is generated, it is pushed upward away from the hair matrix. The portion of hair that remains anchored in the epidermis is called the hair root, while the portion of hair on the skin surface is called the hair shaft. There are three layers of keratinized cells in a hair shaft, the cuticle (surface layer), the cortex (underlying layer) and the medulla (core of the hair).

Answer:

The most common form of skin cancer is basal cell carcinoma , which occurs in the stratum basale layer of the skin and is observed as a waxy bump on the skin surface.

Answer:

Collagen is a fiber located in the reticular layer of the dermis that connects to the papillary layer above the reticular layer and connects to the hypodermis layer underneath. Collagen fibers add protection and limits flexibility in the skin and are not a fibrous protein that forms the basic structure of the hair and nails. The answer is not "a".
Melanin is one of two pigments found in the epidermis. Melanin is a brown, yellow-brown or black pigment produced by melanocytes and is primarily responsible for absorbing UV radiation before it damages nuclear DNA of skin cells in the epidermis. The answer is not "b".
Elastin is a protein found in elastic fibers. Elastic fibers are present in the reticular layer of the dermis and functions to increase flexibility in the skin. The answer is not "c"
Keratin is a protein that is extremely durable, water-resistant and covers the entire epidermal layer of the human body. Keratin also forms the basic structural componentd of the hair and nails. The answer is " d ".