Answer to Question 1
Gas exchange may be impaired if the alveolar septa are thickened and scarred. It also may be impaired if pulmonary blood flow to a portion of the lung is obstructed or by blockage of pulmonary capillaries by fat emboli or foreign material. Also, if the pulmonary alveoli become filled with fluid or inflammatory exudates, inspired air cannot enter the diseased alveoli, and pulmonary gas exchange is impeded.
Answer to Question 2
More technically difficult to perform; may lead to spontaneous abortion and limb deformities
Regulation of heat exchange in the skin.
Bacteria exchange DNA by several processes
Gas exchange occurs at the alveolar capillary membrane.
A model for RecA-mediated strand exchange
Consequences of a double exchange occurring between two nonsister chromatids
Forces affecting capillary exchange