Final answer:
In animal connective tissue, collagen fibers provide tensile strength, while keratin is key in the animal epidermis. In plant cell walls, cellulose fibers play a critical role in providing structural support.
Step-by-step explanation:
The main structures providing tensile strength are different in animal connective tissue, the animal epidermis, and plant cell walls, though they each serve to maintain structural integrity.
- Animal connective tissue: The primary source of tensile strength in animal connective tissue is collagen fibers. These fibers are flexible and fibrous proteins that prevent the tissue from being torn or separated from surrounding tissues. Dense connective tissue, a specific type of connective tissue proper, contains many fibers that provide both elasticity and protection and includes structures like ligaments and tendons.
- Animal epidermis: The main protein providing strength in the animal epidermis is keratin, found within stratified squamous epithelial cells. While the epidermis itself provides a protective barrier, the dermis layer beneath contains collagen and elastin fibers that contribute to the strength and elasticity of the skin.
- Plant cell walls: The tensile strength in plant cell walls is primarily provided by cellulose fibers. These fibers are part of a complex matrix that gives support and rigidity to the plant structure, hence playing a crucial role in the maintenance of the plant's shape and growth.