What type of skeleton is characterized by internal support structures, such as bones or cartilage?

The correct response is based on the defining characteristics of an endoskeleton, which is an internal support structure found in vertebrates and some invertebrates. Unlike exoskeletons, which are external and provide protection from the outside, endoskeletons are located within the body. They consist primarily of bones and cartilage, contributing to the overall framework of an organism while allowing for growth and movement.

The endoskeleton provides not only structural support but also a site for muscle attachment, enabling locomotion and movement. Additionally, bones within an endoskeleton can protect vital organs, such as the brain and heart. This internal skeleton can grow as the organism grows, unlike exoskeletons, which must be periodically shed and regrown.

Other types of skeletons, like hydrostatic skeletons, rely on fluid pressure for support and movement, and cartilaginous skeletons specifically refer to structures made of cartilage, emphasizing one of the materials found in broader endoskeleton classifications.