Final answer:
The two primary reasons for long journeys by individuals from various regions during classical times were the pursuit of trade and the spread of religion. The treacherous Silk Roads were central to the circulation of exotic goods and ideas, while religious motivations were fueled by the propagation of faiths like Buddhism and Christianity.
Step-by-step explanation:
The two primary reasons why individuals from Central Asia, China, India, Southeast Asia, and the Roman Empire undertook long journeys during classical times were trade and religion.
Extensive trade routes like the Silk Roads facilitated the exchange of goods, including silk, spices, porcelain, and other fine materials, while incurring various risks such as banditry, extreme weather, and political conflicts. The spread of religions like Buddhism and the desire to propagate Christianity also motivated people to travel vast distances.
Trade was driven by both the necessity and the profitability of obtaining goods not available locally. Exotic items from distant lands were highly sought after, creating a lucrative market for those who dared to traverse difficult terrains and negotiate with different cultures and authorities.
Religious zeal was equally influential, with travelers embarking on treacherous journeys to spread their faith, as seen in the efforts of Christian missionaries or Buddhist teachers, who became purohita, or advisors, in regions like Southeast Asia.