Final answer:
The most important factor in determining population patterns in East Africa is climate and geography. This is because the livelihood of the majority of the population depends on agricultural activities that are directly affected by these conditions.
Step-by-step explanation:
The question asks which factor plays the most important role in determining population patterns in East Africa. In the context of East Africa, the most influential factor is likely climate and geography (option d). The region's population distribution is heavily influenced by its geography, such as available arable land for agriculture, and climate, especially as climate change forces migrations due to changing agricultural conditions. Political stability (option c) also plays a role, as seen in Somalia's fragmentation, but climate and geography present more fundamental challenges impacting population movements and economic activities.
The majority of East Africa's populations rely on agriculture and live in rural areas; changes in climate and geography directly affect their livelihoods and lead to rural-to-urban migration. Geographic diversity in the region combined with varying climate conditions creates different opportunities and challenges for commerce, health, and overall well-being. The areas affected by political conflict can exacerbate migration and population patterns, but the underlying geographic and climatic conditions shape the fundamental possibilities for settlement and economic activities.