A) 1 month; 4 years B) 6 months; 3 years C) 1 year; 4 years D) 18 months; 3 years Answer: C Topic: Business Cycle Patterns Skill: Recognition 4) According to the National Bureau of Economic Research, since 1920 the average length of reces-sions has been approximately A) one year. B) a year and a half.C) two years.) 1 month; 4 years B) 6 months; 3 years C) 1 year; 4 years D) 18 months; 3 years Answer: C Topic: Business Cycle Patterns Skill: Recognition 4) According to the National Bureau of Economic Research, since 1920 the average length of reces-sions has been approximately A) one year. B) a year and a half. C) two years.
Lungs and Respiratory System of the Chest The respiratory system of the upper abdomen and chest includes the structures involved in the vital delivery of atmospheric air and the exchange of gases between the body and atmospheric air.
The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). The trachea (windpipe) conducts inhaled air into the lungs through its tubular branches, called bronchi. The bronchi then divide into smaller and smaller branches (bronchioles), finally becoming microscopic. Pneumonia: Infection in one or both lungs. 2  Bacteria, especially Streptococcus pneumoniae, are the most common cause. 3  Asthma: The lungs' airways (bronchi) become inflamed and can spasm, causing shortness of breath and wheezing. 4  Allergies, viral infections, or air pollution often trigger asthma symptoms.