Final answer:
The claim that the establishment of Portuguese colonies on the Atlantic islands initiated the Atlantic slave trade for sugar plantation labor is true. The Portuguese were pioneers in using enslaved Africans on Madeira and other islands, which set the stage for the extensive slave trade that catered to the labor demands of New World plantations.
Step-by-step explanation:
The statement that the Canary Islands, Azores, and Madeira Islands would be the start of the Atlantic slave trade due to the Portuguese establishing colonies and using the plantation system to grow sugar is true. The Portuguese started to cultivate sugar on the Atlantic islands such as Madeira and the Azores in the 1400s, and subsequently required a labor force to manage these plantations. They utilized the Atlantic slave trade, which was already in practice among African states, to fulfill this need. By 1444, enslaved people from Africa were brought to work in the sugar plantations, marking a significant beginning of this system. This was the precursor to the larger Atlantic slave trade that supplied labor to plantations across the Americas and Caribbean.
The Portuguese established a foothold in slave trading by exploiting the labor of enslaved Africans in their Atlantic island colonies and selling captives to other European nations. This led to a great expansion of the slave trade once the demand for labor grew in the New World's plantations that produced sugar, tobacco, and later, rice and cotton. Enslaved Africans were subjected to grueling work in the sugarcane fields and in processing the crops into sugar -- a process that was both labor-intensive and dangerous.