> And, 5 million years later, which is the time it took to design this very complicated thing, Mr. R&D came up with a lung system with both an entry point and an exit point, with hollow bones and air-sacs to temporarily store oxygenated air. It was super-efficient compared to any previous lung system and made the best use of the limited oxygen. The animals that received this gift from Mr. R&D were the dinosaurs.

I'd like to know the process by which you evolve from a single-orifice lung system to a dual-orifice lung system in something as complicated as a reptile.