Question

What do porcupine quills, pangolin scales, lions claws, goose feathers and yak hooves have in common
A. They are made of cellulose
B. They are made of keratin
C. They secrete a substance called ambergris
D. None of the above

Answer 1

Hint: The outermost layer of the human body, the skin, acts as the body's first line of defence against foreign particles. It is the human body's largest organ and serves as a barrier between the outside and inside environments. It is made up of several layers, cells, and tissues. Human skin, which is separated into three main areas: dermis, epidermis, and hypodermis, plays a crucial part in overall health and well-being. Nails, claws, hooves, and horns are examples of keratin structures formed by the epidermis.

Complete answer:
Option A: Cellulose fibres provide strength and toughness to a plant's leaves, roots, and stems, making it an ideal structural material.
So, option A is incorrect.
Option B: Keratin is a protein that is deposited in epidermal cells to protect them from damage or stress. Hair, horns, claws, hooves, and nails are all made of this crucial structural element.
So, option B is correct.
Option C: Ambergris is a solid, waxy, combustible material produced in the digestive system of sperm whales. It has a dull grey or blackish colour.
So, option C is incorrect.
Option D: Keratin is a protein found in epidermal cells that protects them from damage and stress. This essential structural element can be found in hair, horns, claws, hooves, and nails.
So, option D is incorrect.

So, Option B is the correct answer.

Note:
The epidermis is the skin's outermost layer, made up of cells called keratinocytes, which are formed of a protein called keratin. The epidermis, which is made up of four layers, protects and safeguards the inside cells and tissues. The epidermis gives rise to epidermal derivatives, which are found in the dermis. Hair follicles, which produce hair on most body surfaces, are the most visible epidermal descendants. Nails, claws, hooves, and horns are examples of keratin structures formed by the epidermis.