What type of tissue is described as having a tough elastic material found between bones of the spine?

The correct choice is cartilage. Cartilage is a specialized form of connective tissue that is both flexible and strong, providing support while allowing for some movement. It is composed of a dense network of collagen and elastin fibers embedded in a gel-like matrix, which gives it its unique properties. In the spine, cartilage is found in the intervertebral discs, where it serves as a cushion between the vertebrae. This cartilage absorbs shock and prevents the bones from grinding against each other, allowing for smooth movement and flexibility of the spine.

Adipose tissue, while a form of connective tissue, primarily functions as a fat storage depot and does not have the structural properties that support the vertebrae. Osseous tissue refers to bone tissue, which provides rigidity and strength to the skeletal system but does not possess the elasticity that cartilage does. Lastly, connective tissue proper encompasses a broad category of tissues that includes loose and dense connective tissues, but it does not specifically refer to the specialized cartilage found in the spine.