Marvel: Superhuman Respiratory System

John Proudstar (Thunderbird)
Thunderbird's lungs were oversized, and his respiratory system was developed in such a way as to allow him maximum wind and endurance with a minimum of oxygen intake. These features made Thunderbird a natural outdoor fighter and athlete.

Mortimer Toynbee (Toad)
Toad's lungs can expand and compress large quantities of air that can be expelled with enough force to knock a fully-grown human off their feet.