Final answer:
Rain shadows primarily occur near large mountains, where moist air rises and loses moisture as precipitation on the windward side, leaving the leeward side arid.
Step-by-step explanation:
Rain shadows primarily occur near large mountains. The rain shadow effect happens when moist air from the ocean rises up over a mountain range, cools down, and precipitates on the windward side. The air that descends on the leeward side is much drier and creates arid conditions. This explains why western China, the leeward side of the Himalayas, is very dry compared to its southern side facing the Indian Ocean, which receives monsoon rains. These conditions affect human activities, as regions under the rain shadow may be less suitable for agriculture due to the lack of rainfall, influencing settlement patterns and land use. This influences human activities as dry conditions affect suitability for agriculture.
Examples of deserts formed by the rain shadow effect include the Mohave and Sonoran deserts in North America and the Atacama region in Chile. The Atacama is on the leeward side of the Andes Mountains where prevailing winds lose their moisture before passing over these highlands. Subtropical deserts, like the Sahara and the Namib, are found between latitudes 30° and 15° north and south, but their aridity is also a result of high-pressure, dry air descending at those latitudes rather than the rain shadow effect.