Q. Which of the following sentences defines air mass correctly ?
Answer: They are large volume of air defined by temperature and water vapor content
Notes: An air mass is a large body of air that has uniform temperature and humidity characteristics. It forms over a source region, such as land or water, and can cover thousands of square kilometers. The classification of air masses is based on their temperature (tropical, polar) and moisture content (maritime, continental). This definition aligns with the correct answer: "They are large volume of air defined by temperature and water vapor content."