🔍 Key Concepts

• Air masses and how they interact • Difference between fronts: cold, warm, stationary, occluded • What happens when there is no horizontal movement of the air masses

💭 Think About

• Ask yourself: which type of front involves two air masses meeting but neither one is advancing over the other? • Which named fronts (cold, warm, occluded) specifically involve one air mass moving and replacing another? • If a front is described mainly by motion (cold air advancing vs warm air advancing), does that match the situation in the question where there is no movement?

✅ Before You Answer

• Verify which front forms when air masses meet and one actively displaces the other. • Identify the front that, by definition, occurs when the boundary is not moving significantly. • Eliminate any option whose definition requires motion of one air mass into the other.