A rock contains 12.5% of its orignal K40 (half life = 704 million years). How old is the rock?

  1. About 1,400 million years old
  2. About 2,100 million years old
  3. About 2,800 million years old
  4. About 700 million years old


About 2,100 million years old

Environmental & Atmospheric Sciences

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In the western Pacific, the most powerful storms are called

A) typhoons. B) tropical anticyclones. C) hurricanes. D) monsoons. E) tropical depressions.

Environmental & Atmospheric Sciences

In which of the following areas would one likely find Aridisols?

A) northern Europe B) the selva in Brazil C) the U.S. southwest D) marine west coast climates

Environmental & Atmospheric Sciences

In what geologic period did lobe-finned fish adapt to terrestrial environments?

A) Cambrian B) Devonian C) Triassic D) Ordovician

Environmental & Atmospheric Sciences

In the figure below, two people are looking at the same point in the sky. Which of the following types of light does person A see?  

A. unscattered light B. scattered light

Environmental & Atmospheric Sciences