Atelectasis be bibasal in pattern. Chest CT or Bronchoscopy may be necessary if the cause of atelectasis is not clinically apparent. Direct signs of atelectasis include displacement of interlobar fissures and mobile structures within the thorax, overinflation of the unaffected ipsilateral lobe or contralateral lung, and opacification of the collapsed lobe. Atelectasis may be an acute or chronic condition. In acute atelectasis, the lung has recently collapsed and is primarily notable only for airlessness. In chronic atelectasis, the affected area is often characterized by a complex mixture of airlessness, infection, widening of the bronchi (bronchiectasis), destruction, and scarring (fibrosis). The atmosphere
Body hair prevent diseases. Markus J. Rantala of the Department of Biological and Environmental Science, University of Jyväskylä, Finland, said humans evolved by "natural selection" to be hairless when the trade off of "having fewer parasites" became more important than having a "warming, furry coat". P.E. Wheeler of the Department of Biology at Liverpool Polytechnic said quadrupedal savannah mammals of similar volume to humans have body hair to keep warm while only larger quadrupedal savannah mammals lack body hair, because their body volume itself is enough to keep them warm. Therefore, Wheeler said humans who should have body hair based on predictions