Final answer:
China and the United States were not equipped to join the early years of world exploration due to China's lack of industrialization and the U.S.'s isolationist policies.
Step-by-step explanation:
China was among the countries not adequately equipped to join early world exploration, when many European and a few Asian countries started to expand their territories and influence around the globe.
This was due to a combination of factors, despite China's significant wealth, population, and historical tradition of innovation and invention.
While industrialization played a crucial role in equipping nations with the technological and economic means to explore and colonize new lands, China did not follow the same industrial path that Western nations did during the nineteenth century.
Historians suggest a variety of reasons for China's lack of industrialization, such as its relatively self-sufficient economy, resistance to adopting Western technologies and practices, and perhaps geopolitical considerations of the time.
Similarly, the United States did not participate early in global explorations due to its isolationist policies, keeping a limited military force and navy until its imperial advances necessitated a change by the end of the nineteenth century.
It maintained a strategic diplomatic approach to avoid foreign entanglements, thanks in part to its geographic location, which provided a natural barrier against many overseas conflicts.
Africa was largely impenetrable to Europeans before the mid-nineteenth century due to its challenging geography, the lack of navigable rivers by sail, and lethal diseases, particularly a virulent form of malaria, which Europeans lacked resistance to.
Only by the second half of the nineteenth century were Europeans able to make significant inroads into the African interior as medical advances and technology improved.