Final answer:
Insects have a hard outer exoskeleton made of chitin, while humans have an internal skeleton made of bone and cartilage. Insects have specialized appendages and body segments, differing significantly from human skeletal structure.
Step-by-step explanation:
Insects have a hard outer exoskeleton, while humans have an endoskeleton. The exoskeleton of insects is made of chitin, a type of polysaccharide, which provides support and protection to the insect's body and is also involved in muscle attachment. Insects, such as beetles and butterflies, may have wings that are part of the exoskeleton. Unlike insects, humans have an internal skeletal structure made of bone and cartilage that supports the body and facilitates movement.
Insects have various body parts such as a head, thorax, and abdomen, six legs, a pair of antennae for sensing chemicals, compound eyes, and specialized mouthparts adapted for different feeding habits. By contrast, the human skeleton includes long bones, flat bones, and irregular bones, all of which play specific roles in body mechanics and protection of vital organs.
It is important to note that while insects and spiders are both arthropods, spiders are not insects as they have eight legs whereas insects have six. Also, insects have distinct body segments and an elongated heart that stretches through much of their body, unlike the centrally located heart in vertebrates like humans.