A ________ is a boundary between two air masses with different temperatures.

A ________ is a boundary between two air masses with different temperatures.

• A. Front
• B. Ridge
• C. Trough
• D. Jet

Answer: (A)

A front is the boundary between two air masses with different temperatures. It forms where warm and cold air meet, and the temperature contrast along that boundary causes air to rise, often leading to clouds and precipitation and shifts in wind. The other terms describe upper-atmosphere features: a ridge is an elongated area of higher pressure aloft, a trough is an elongated area of lower pressure aloft, and a jet is a fast-moving current of air high in the atmosphere. Since the question focuses on a boundary defined by temperature differences between air masses, front is the correct term.

A front is the boundary between two air masses with different temperatures. It forms where warm and cold air meet, and the temperature contrast along that boundary causes air to rise, often leading to clouds and precipitation and shifts in wind. The other terms describe upper-atmosphere features: a ridge is an elongated area of higher pressure aloft, a trough is an elongated area of lower pressure aloft, and a jet is a fast-moving current of air high in the atmosphere. Since the question focuses on a boundary defined by temperature differences between air masses, front is the correct term.