Pulmonary alveolus thin fluid coating within all alveoli. The fluid coating is produced by the body in order to facilitate the transfer of gases between blood and alveolar air. The surfactant is produced by the type II cells which are the most numerous cells in the alveoli, yet do not cover as much surface area as the squamous alveolar cells (a squamous epithelium). Type II cells also repair the endothelium of the alveolus when it becomes damaged. Insufficient surfactant in the alveoli can contribute to atelectasis (collapse of part or all of the lung). Without pulmonary surfactant, atelectasis is a certainty; however,
Destroy All Humans! 2 worm to crawl around, eating nearby humans. The Anti-Gravity Field, which creates a small point of high gravity, which pulls anything, including humans, into it before exploding, destroying anything. "Destroy All Humans! 2" received generally positive reviews from critics. Aggregating review websites GameRankings and Metacritic gave the Xbox version 76.61% and 74/100 and the PlayStation 2 version 75.75% and 74/100. GameZone stated that "The new weapons and body snatching ability just add more fun to a game with huge open worlds and the plentiful side missions" and that the ""game actually supersedes the original"". The AI was criticized by TeamXbox,