Which is the most accurate summary of the article?
a) national parks provide rare opportunities for humans to interact with many species of wild animals.
b) america must preserve its national parks so that future generations will be aware of the sacrifices that were made to create the parks.
c) the national parks are important places in which people can learn about nature and the relationship between human society and the natural world.
d) without national parks americans will have no way to learn about the types of biomes that once were spread throughout the north american continent.