Final answer:
Mountain-building affects weather patterns through the rain shadow effect, where mountains cause precipitation on the windward side and create arid conditions on the leeward side. The correct answer is option (A).
Step-by-step explanation:
The mountain-building process significantly alters weather patterns through the phenomenon known as the rain shadow effect. When moist air currents encounter a mountain range, they are forced upward. As air rises, it cools, causing the water vapor to condense and fall as precipitation on the mountain's windward side. This leads to the wet and lush climates typically found on the side of the mountains where the wind comes from.
Conversely, as the air descends on the leeward side of the mountain, it warms up, leading to lower humidity and often creating arid conditions. This explains why one side of a mountain range may be characterized by forested areas or dense vegetation while the other side may feature desert-like conditions.
Mountains act as barriers to prevailing wind patterns, capturing moisture and thus causing differences in precipitation. Mountains block wind patterns, resulting in heavy precipitation on the windward side and a rain shadow on the leeward side. This is evidenced by various global examples, such as the Cascades and Sierra Nevada ranges, which cause semi-arid conditions in their rain shadow zones, or the Andes, which contribute to the dryness of the Atacama Desert. Given this understanding, the correct option from the provided choices would be (A) Mountains block wind patterns, causing precipitation on the windward side and a rain shadow on the leeward side.