Final Answer:
One of the most easily recognized discontinuities across a front is 1) A change in temperature
Step-by-step explanation:
One of the most easily recognized discontinuities across a front is a change in temperature. Fronts are boundaries between air masses with different temperature and humidity characteristics. When a front passes through an area, there is often a noticeable temperature shift, with a distinct contrast between the air masses on either side of the front.
Option 2, "An increase in cloud coverage," is not necessarily a universal indicator of a front. While fronts can be associated with changes in weather patterns, cloud coverage can be influenced by various factors. Option 3, "An increase in relative humidity," may occur but is not as consistently linked to front passage as a change in temperature.
In summary, 1) recognizing a change in temperature is a key observational cue for identifying the presence of a front. This temperature contrast is indicative of the boundary between different air masses, which can lead to weather changes such as precipitation and storms. Meteorologists use these temperature shifts to identify and track fronts, contributing to weather forecasting accuracy.