The decay of uranium isotopes is used to provide information about the age of Earth.
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Explanation:</h3>
Isotopes of Uranium U-232, U-233 , U-234 , U-235 , U-236 , U-238 are used as fuel in nuclear reactors or as explosives for nuclear weapons. Uranium 238 is not very radioactive and it constitutes for nearly 99.3% of natural uranium on Earth and has the longest lifetime: its period is 4.5 billion years, about the age of Earth.
Use of radiometric dating techniques help in defining the age of substances (natural or man-made) using the known decay rates of radioactive elements. Each element has an individual decay rate and half life time.
Two Uranium isotopes (U-238 and U-235) are used for radiometric dating. Both the isotopes have different decay rates and half life period. Both are unstable and radioactive. Since two different isotopes produce two different decay clocks (one as a reference to other), it is beneficial in accurately determining the age of samples. The age of earth (rocks or other natural elements) can be easily determined using Uranium isotopes.
The correct answer is - 1,180 km.
North America and Europe move away from one another, though the two plates, the North American and Eurasian are merging together on the other side. Since the rate of moving away is 2 cm per year, and the current distance is 1,184 km between North America and Europe, the distance between them 200,000 years ago was 1,180 km.
To get to the result we only need to multiply the number of years with the annual movement
2 x 200,000 = 400,000
Than divide the result with 100,000, as that is how much cm are in one km
400,000 / 100,000 = 4
And we get 4 km, in this case 4 km less, thus the distance between the two, 200,000 years ago, was 1,180 km.
Sinks of carbon dioxide can be farms grasslands or forest
