Final answer:
Tendons, composed of dense regular connective tissue, play a crucial role in the attachment of skeletal muscles to bones, enabling movement.
Step-by-step explanation:
The connective tissue that directly plays a key role in the attachment of skeletal muscles is tendons. Tendons are made up of dense regular connective tissue consisting of collagen fibers aligned in parallel. This structure allows tendons to be incredibly strong and effectively connect muscle to bone, facilitating movement. Ligaments, on the other hand, are also composed of dense regular connective tissue but serve the function of holding bones together. Cartilage provides a smooth surface at the joints for bones to move over and is also a type of dense connective tissue but does not attach muscles to bones. Adipose tissue is a type of loose connective tissue that serves as energy storage and insulation but is not involved in attaching muscles to bones.