Answer:
D. Americans
Explanation:
The antecedent is a noun that replaces the subject, the thing doing the action.
In the sentence instead of saying americans again it says their.
The Yellowstone National Park is valuable to the US from many perspectives; protecting the environment, offering recreation, bringing in money from tourism etc.
Explanation:
The Yellowstone National Park is one of the most famous national parks in the world. The reason for that is that this national park has lot to offer; interesting physical features, geysers, beautiful forests, wildlife... This brings in lot of benefits with it.
The conservation of Yellowstone National Park is very important for conservation of the species living in it, as well as being very important for reintroduction of species that were extinct in the area, such as the wolf. Aesthetically it is beautiful, with all of its diversity in nature and land forms. From practical point of view, the people use it for relaxing, recreation, and it brings in lot of revenue from tourism.
