The Pathway
• air enters the nostrils
•passes through the nasopharynx
•the oral pharynx
•through the glottis
• into the trachea
• into the right and left bronchi, with branches and rebranches into
• bronchioles each of which terminates in a cluster
• alveoli
The answer is A) An inner skeleton made of bone or cartilage. Vertebrates have a column of bones that supports the body and protects the spinal cord, while invertebrates are animals that either have a soft body or a hard outer casing covering their body.