[填空题]Modern aircraft fly at the interface between the troposphere/对流层/ ( )stratosphere /平流层/,roughly equivalent to a cruising altitude of 32,000 to 45,000 feet. ( ) the troposphere,planes fly more smoothly and experience less turbulence and inclement/恶劣的/weather.The height of troposphere ( ) altitude and season,passengers are protected from high altitude atmospheric/大气的/condition by pressurized/加压的;受压的/cabin environment that ( ) creates its own medical ramifications/分支;衍生物/.The comfortable and relaxed atmosphere may be ruined by a doctor-seeking announcement:“Ladies and gentlemen,there is a mid-age woman suffering from heart attack,if you are a medical professional,please come to the front cabin.”In 2014,it is ( ) that 2.75 billion people travel aboard commercial airlines every year,and 44,000 in-flight medical emergencies occur worldwide each year.A sudden call for assistance in the cabin may present the flight attendant and responding medical professionals in a panic.