Read this paragraph
Rocky Mountain National Park, nicknamed "Rocky," is a true marvel of the American West. Visit this place set aside for its natural beauty and you will encounter a variety of animals, plant life, and
even climates. There are four ecosystems inside Rocky Mountain National Park, riparian, montane, subalpine, and alpine tundra. You might see a moose or mule deer drinking from a pond in a riparian
ecosystem, which are areas that are near streams or lakes. Riparian ecosystems can be found within the other three ecosystems. The montane ecosystem is the lowest in elevation at Rocky. There you
will find ponderosa pine trees and wide-open mountain meadows, lush with wildflowers in the summer. Climb a little higher into the subalpine ecosystem, where long winters and short, cool summers
make up the climate. Look high into a limber pine tree and you might spot a Clark's nutcracker, nibbling on pine seeds. Finally, the highest elevation in Rocky is the alpine tundra. Bitter cold and wind-
blasted defines this ecosystem with its jagged mountain tops that are capped with snow even in late August. Each of these ecosystems has a quality all its own, but they are all interconnected,
comprising a true American treasure: "Rocky"
Which of these best states the main idea?
a. There are four ecosystems inside Rocky Mountain National Park, riparian, montane, subalpine, and alpine tundra.
b. Rocky Mountain National Park, nicknamed "Rocky," is a true marvel of the American West,
c. The riparian ecosystem can be found within the other three ecosystems
d. Each of these ecosystems has a quality all its own, but they are all interconnected, comprising a true American treasure: "Rocky"