What are the two tissue types found in the vertebrate skeleton?

The vertebrate skeleton is primarily composed of two main tissue types: cartilage and bone.

Cartilage serves various functions in the skeleton, including providing flexible support in structures such as the nose and ear, as well as forming the precursor to bone in the early stages of development. During the growth process, cartilage is gradually replaced by bone in a process known as endochondral ossification, a key aspect of skeletal development in vertebrates.

Bone, on the other hand, is a more rigid and mineralized tissue that makes up the majority of the skeleton in adult vertebrates. It provides structural support for the body, protects vital organs, facilitates movement by serving as points of attachment for muscles, and plays a crucial role in the housing and production of blood cells within the bone marrow.

The other options include tissue types that are associated with the skeleton but do not form the fundamental structure of the skeleton itself. Ligaments and tendons connect bones to muscles and bones to other bones, respectively, but they are not part of the skeleton. Fibrous tissue also plays a supportive role but is distinct from cartilage and bone. Thus, the correct answer identifies the two essential tissue types that constitute the vertebrate skeleton: cartilage and bone.