Final answer:
The underlying cause of weather is the flow of heat from warm regions to cold regions, driven by convection. This process is influenced by the circulation of the atmosphere and oceans, which redistributes heat and creates weather patterns.
Step-by-step explanation:
The underlying cause of weather is that heat flows from warm regions to cold regions. This process, called convection, is driven by the large-scale flow of matter, such as the flow of hot air from the tropics to the poles and the flow of cold air from the poles toward the tropics.
The heating of the Earth's surface by sunlight causes the atmosphere and oceans to redistribute heat, resulting in weather patterns.