How many types of economic system exist in a country?

Which statement describes why the us forest service is important a-it protects ecosystems, supervises public access of lands, and manages wilderness areas. b-it supervises public access of lands, manages wilderness areas, and enforces federal wildlife laws. c- it manages wilderness areas, enforces federal wildlife laws, and foreign governments with international conservation efforts. d- it enforces federal wildlife laws, foreign governments with international conservation efforts, and protects ecosystems.

Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

How has the geography of india made it difficult for its people to expand before modern technology?