Final answer:
The changes in American economic activities after the conquest were closely tied to the marked reduction of the indigenous population.
Step-by-step explanation:
The changes in American economic activities after the conquest had a direct relationship with the marked reduction of the indigenous population. The arrival of Europeans in the Americas brought about significant shifts in the economic systems, including the establishment of European sugar plantations that required labor. As the native populations were wiped out or enslaved, enslaved Africans were brought in to fill the labor gap and support the West Indies sugar economy. Additionally, the colonization efforts led to the depletion of local resources, violence against indigenous peoples, and the imposition of new economic conditions.