One of nature’s most unique proteins provides cells with an abrasion-resistant, a condition known as:
a) stratum germinativum
b) dermal papilla
c) melanin
d) keratin

The correct answer is D) Keratin.

Explanation:

Keratin is a fibrous protein produced by epithelial cells called keratinocytes. They form the tough structural parts of the body like nails, claws, hairs, horns, etc, which are resistant to abrasion, wear and tear.Melanin is a protein pigment produced by cells called melanocytes.  Skin gets coloured due to this pigment.The epidermis of the skin is divided into five layers: Stratum germinativum, Stratum spinosum, Stratum granulosum, Stratum lucidum and Stratum corneum.The Stratum germinativum is the deepest layer found in the epidermis and is made up of a single cuboidal or columnar epithelial cell layer. Dermal papilla is formed by the finger-like intrusion of the dermis layer of the skin into the epidermis. It is mainly responsible for providing oxygen and nutrients to the lower layers of the epidermis.

The fossils are defined as the remnants of ancient plants and animals that were buried millions of years ago. The fossils that are found in the present day includes both heterotrophs and autotrophs.

Those organism that can prepare their own food in the presence of sunlight, water and carbon dioxide, by the process of photosynthesis are considered as the autotrophs. They are also known as the producers. Some of the examples of autotrophic fossils are Gangamopteris and Glossopteris fossil plant.

Those organisms that cannot prepare their own food and are dependent on the autotrophs are known as the heterotrophs. Some of the examples of heterotrophic fossils are dinosaurs.