Ameteorite was found to contain 40 argon-40 atoms for every 10 potassium-40 atoms. the half-life of postassium-40 is 1.25 billion years. assuming no loss of daughter isotopes, how old is the moon rock?

2.5 billion years old

3.75 billion years old

6.75 billion years old

10.5 billion years old

It is reasonable to assume that nations with a low total fertility rate (tfr) and a modest amount of population growth are in

When volcanoes erupt, magma (hot, molten rock) rises toward the surface of the earth. as magma cools, solid rock forms. this rock contains substances from the interior of the earth. which of the following natural resources is likely to be plentiful near subduction zones where volcanic activity has occurred in the past?

Although china’s total economic output, measured by gross domestic product (gdp), is third largest in the world, it is considered a developing nation. what is most likely the most important factor for this designation? a. china’s government spends money on things that do not benefit human development. b. china has a large population, so its gdp per person is only modest. c. china has a strong economy but weak literacy and school attendance rates. d. china’s high rates of disease offset the country's economic gains.