Which of the following reasons contributed to europeans seeking african slaves during the 15th to 18th centuries? a. africans' advanced navigational knowledge transatlantic voyages succeed. b. africans were easily subdued because of their lack of immunity to european diseases c. africans were familiar with european agricultural methods d. europeans did not have to trade anything in exchange for african slaves

d. Europeans did not have to trade anything in exchange for African slaves

Explanation:

The first Europeans to reach the coasts of Guinea were the Portuguese. The first European who bought African slaves in the region of Guinea was Antão Gonçalves, a Portuguese explorer from 1441 AD. Originally interested only in the trade of gold and spices, they established colonies on the uninhabited islands of São Tomé. In the sixteenth century, Portuguese settlers discovered that these volcanic islands were perfect for growing sugar. The cultivation of sugar is labor-intensive, and the Portuguese found it difficult to attract workers to the area as a result of high temperatures, lack of infrastructure and harsh living conditions. To cultivate sugar the Portuguese made use of an important number of African slaves. The Fort San Jorge de la Mina on the British Gold Coast, originally built by Africans for the Portuguese in 1482 with the objective of controlling the gold trade, became an important deposit of slaves that were transported to the New World.

The increase in penetration in America by the Portuguese created a greater demand for labor in Brazil, mainly to harvest and work in the mines. Labor-based economies of slaves quickly expanded to the Caribbean and southern belt of what is now known as the United States, where Dutch merchants brought the first African slaves in 1619. These areas developed an insatiable demand for slaves. As European nations became more powerful, especially Portugal, Spain, France, Great Britain and the Netherlands, they began to fight for control of the African slave trade, with little effect on local African and Arab trafficking. The British colonies in the Lesser Antilles and their effective naval control of the Mid-Atlantic forced other large countries to abandon their companies as a result of cost inefficiencies. The British Crown granted privileges to the Royal African Company, which held a monopoly on the routes of the African slave trade until 1712.

the answer is

d.summerains, the last one