PART 1:  The FEV1/VC ratio isclinically significant because it is an indicator of[\"alveolar surface area\", \"airway resistance\", \"alveolarpressure\", \"respiratory rate\"] . A healthy individual'sFEV1/VC ratio is near [\"50%\", \"80%\", \"90%\",\"100%\"], while an individual with an obstructive lungdisease will likely have a FEV1/VC ratio of less than[\"50%\", \"80%\", \"90%\", \"100%\"] because of a[\"decrease in resistance\", \"merging\", \"dilation\",\"collapsing\"] of the small airways.

PART 2: Tidal volume increased after exercisebecause CO2 production [\"increased\",\"decreased\"]  owing to the increased metabolicrate of exercising skeletal muscle. This change in CO2 stimulatedthe [\"peripheral\", \"central\"][\"baroreceptors\", \"photoreceptors\", \"osmoreceptrs\",\"chemoreceptors\"] resulting in [\"faster\",\"slower\"] and  [\"shallower\",\"deeper\"] breathing. As a result of the tidal volumeincreasing, inspiratory and expiratory volumes both[\"significantly increased\", \"significantly decreased\", \"didnot significantly change\"] while vital capacity[\"significantly increased\", \"significantly decreased\", \"didnot significantly change\"]. Since total lung capacity isequal to the vital capacity plus residual volume (which is aconstant), total lung capacity  [\"significantlyincreased\", \"significantly decreased\", \"did not significantlychange\"]      .