All three regions were greatly affected by interactions with Europeans. However, the outcomes were very different in each place, mostly due to the motives of the Europeans at the times they came into contact with the peoples of those places.
To start off, the Americas were transformed entirely by interactions with Europe. The Spanish, Portuguese, and English (and the French and Dutch to a lesser extent) sought to completely colonize the vast regions of the New World. In Central and South America the native populations were forcibly converted to Catholicism and enslaved in order to serve the agenda of their new European rulers. Old systems of government and culture were greatly dismantled to serve this purpose. In North America, the English sought to set up colonies that were mostly populated by Europeans, pushing the native peoples to the periphery, although contacts were maintained to facilitate trade and military alliances.
India was a different story. Ever since the first European trading outposts were established in India in the late 15th century, there was a great interest in exploiting the many resources of this land. In the mid 18th century, Great Britain started seizing large swaths of the subcontinent. Most of this was administered by the East India Company and was meant to enrich the coffers of its stakeholders as well as the English Crown. Later on, Britain ruled India through local governors. The Indian people were treated as subjects of the English Crown. While many European missionaries did go to India with the intent of "civilizing" its people, most local Indian customs, traditions, and institutions remained intact.
Sub-Saharan Africa did not see much contact with Europeans until the latter part of the 19th century. When this happened though, there was a mad dash to carve up the continent among European powers known as "the Scramble for Africa." By the end of the century, nearly all of Africa was ruled by different European countries. Borders were drawn up with little to no concern for tribal relations. As a result, conflicts between African peoples who were historically enemies, but now forced into the same political and administrative unit increased. Despite all of this, many of the borders that were drawn up by Europeans that defined the colonies still exist as the frontiers between African countries today.