What evidence do the authors include to support the central idea that the sugar plantations' cheap labor source changed from enslaved people to indentured Indians?

Hi. You did not submit the text to which this question refers, which makes it impossible for it to be answered. However, after searching for your question on the internet, I was able to find another question exactly like yours that had the text "Sugar Changed the World." If that's the case for you, I hope the answer below will help you.

The evidence is at the moment Gladstone asks the shipping company to send workers to him. He specifically asks for workers and not slaves.

Explanation:

"Sugar Changed the World" is a story that addresses the importance of sugar in the creation of societies, especially in European colonies spread across America. As sugar became a very popular spice, its exploitation shaped the society of the colonies, established slave labor, the exploration of native territories and the positioning of Africans and indigenous people in this process. One of the great factors shaped by the exploitation of sugar was the adoption of indigenous workers who were hired to replace African slaves in the cane fields. Within this text, the evidence that the authors use to show that this moment happened is identified when Gladstone, a plantation owner, asks the shipping company not to take slaves for him, but hired workers.