The boundary between contrasting air masses is known as what?

• A. Weather front
• B. Jet stream
• C. Thunderstorm
• D. Cyclone

Answer: (A)

When two air masses with different temperatures and humidity meet, the boundary where their properties shift is called a weather front. This boundary causes the air to rise and cool, leading to cloud formation and often precipitation, which is why fronts are tied to changes in weather. The jet stream is a high-altitude, fast-moving wind belt, not the boundary between air masses. A thunderstorm is a weather event that can occur along fronts, but it’s not the boundary itself. A cyclone is a large low-pressure system, again not the boundary between contrasting air masses.