The half life of Uranium-238 is 4.5 billion years. Approximately how much of the radioactive Uranium-238 parent isotope is left in a rock that is 4 billion years old?
- 25%
- 45%
- 55%
- 75%
55%
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In the diagram below, the importance of the falling precipitation at "A" for the global carbon cycle is that
A) the falling rain makes carbon in the atmosphere more inert, giving it much greater potential to act as a greenhouse gas and warm the Earth.
B) the falling rain brings CaCO3 which was trapped in the atmosphere to the surface, cooling the Earth.
C) the falling rain lubricates the Earth's surface, making crustal deformation more likely, which would bring carbon stored in the lithosphere back up to the atmosphere, warming the Earth.
D) CO2 combines with water to form H2CO3, removing carbon from the atmosphere and cooling the Earth.
The Himalayan Mountains resulted from an orogeny
a. True b. False
If a frontal zone exists, it will likely be shown on a surface weather map
Indicate whether the statement is true or false
_______ as a population less than ten percent of its previous levels
Fill in the blank(s) with correct word