A front forms when _____.
warm air begins to rise and cool
two different types of air masses meet
two of the same type of air masses meet
cool air begins to sink and warm
The correct answer should be when two different air masses meet. A front is usually either cold or warm based on the way the masses are coliding which can either result in a drop or an increase in temperature. This is useful because this is how cyclones work and this can help with seeing precipitation patterns that will occur.
