Question

saving the manatee
the florida manatee, a subspecies of the west indian manatee, is a large ocean mammal found in floridas rivers and coastal areas. unfortunately, the states population of manatees has dwindled significantly over the years. although the manatee has no natural predators, humans have contributed to many manatee deaths, mainly through boat collisions. the loss of warm - water habitats has also hastened the manatees decline. aerial surveys performed in the early 1990s found an estimated 1,267 manatees in florida. because of conservation efforts by several organizations, however, the number of manatees has rebounded recently. the creation of manatee protection zones—areas that boaters must avoid or drive through more slowly—has been particularly effective. as a result of these efforts, more than 6,000 manatees are found in florida today.
what is the main, or central, idea of the passage?
if boats are allowed at all in manatee protection zones, they are required to go at slower speeds.
thanks to conservation efforts, florida manatee populations have increased.

Explanation:

The passage starts by introducing the Florida manatee and its population decline due to human - related (boat collisions) and habitat (loss of warm - water habitats) issues. Then it mentions conservation efforts (like manatee protection zones) and how these efforts have led to an increase in the manatee population (from an estimated 1,267 in the early 1990s to more than 6,000 today). The first option is just a detail about the protection zones, while the second option summarizes the overall story of decline and then increase due to conservation.

Answer:

Thanks to conservation efforts, Florida manatee populations have increased.