Comparison of the avian 'unidirectional' respiratory system (a) where gases are exchanged between the lungs and the blood in the parabronchi, and the bidirectional respiratory system of mammals (b) where gas exchange occurs in small dead-end sacs called alveoli (From: West et al. 2007).s a result, air coming into a mammal's lungs is mixed with 'old' air (air that has been in the lungs for a while) & this 'mixed air' has less oxygen. So, in bird lungs, more oxygen is available to diffuse into the blood (avian respiratory system).
The Power of Sympathy or The Triumph of Nature (1789) is a cautionary novel by William Hill Brown (1765-1793). It is based on an actual case of seduction and incest in col â¦ onial America. It is considered by many to be the first American novel.
How Terrible It Is To Love Something That Death Can Touch. Short Story by: GZ123. Had to write a Gothic Short story for English literature. I love writing, but I rarely finish anything I start, so I thought I'd post this on here.