Answer:
Farmers expand their farmlands by destroying the ecosystems, with the tropical rainforests and grasslands experiencing the most damage.
Explanation:
Central and South America have populations that grow. This growth is not very big, like in Africa for example, but it is a steady one. The more people there are, the more food is needed. This means that more and more land is needed for agriculture, meaning that the natural ecosystems are targeted for this purpose.
In order to satisfy the demand in the markets, but also to make more profit, the farmers clear out the vegetation that grows naturally, be it by cutting it down or burning it. This is leading to the rapid destruction of tropical rainforests and grasslands, and in their place, there are farmlands, while the animals that go away with the removal of the vegetation are replaced with cattle.
