An illustration includes Amphibian, Reptilian, and Mammalian lungs. Color representation of parts marked are blue for nostrils, mouth, and throat; yellow for Trachea and purple for Lung.

1. Amphibian - Lung is thin, a little more than a sac with ridges.
2. Reptile - Lung has little more surface are compared to amphibian.
3. Mammal - Lung has greatest surface area among animals.