Which of the following functions is associated with the skin?

a. Cartilage: Cartilage is a type of connective tissue found at the ends of bones in joints. It provides a smooth, elastic surface that cushions the bones and reduces friction during movement.

b. Tendon: Tendons are tough, fibrous bands that connect muscles to bones. They do not reduce friction at joints.

c. Fibrillin: Fibrillin is a protein component of connective tissue, but it's not a specific structure like cartilage and doesn't directly reduce friction in joints.

d. Osteocytes: Osteocytes are mature bone cells. They are not located at joints and don't play a role in friction reduction.

a. Elastic connective tissue: This tissue contains elastic fibers and fibroblasts, providing elasticity and flexibility but not the tightly packed, parallel collagen fiber arrangement.

b. Dense irregular connective tissue: This tissue has collagen fibers arranged in a random, irregular pattern, providing strength in multiple directions but not the parallel arrangement.

c. Reticular connective tissue: This tissue contains reticular fibers forming a network to support soft organs but does not have densely packed collagen fibers.

d. Dense regular connective tissue: This tissue has fibroblasts packed tightly between parallel arrays of collagen fibers, providing great tensile strength along the direction of the fibers. It is found in tendons and ligaments.