We should expect that the rat will have have more difficulty in learning the task compared to a normal rat. This is because the rat has been injected with a certain drug that oppresses the dopamine activity. And then the rat is placed in an operant chamber where a lever-pressing task is shaped through positive reinforcement.
1.Frost Wedging (Freeze-Thaw)
Water expands by 9 percent when it freezes. As it expands, it exerts up to 4.3 million pounds per square foot of pressure. Since water seeks low points, repeated freezing and thawing can lead to deep vertical fissures as cracks are extended downward. Cracks that allow entry of roots lead to similar wedging.
2.Crystal Formation
Crystal formation cracks rock in a similar way. Most water contains dissolved salts. When water in rock fissures evaporate, the salt concentration increases, which leads to crystallization. This occurs in arid regions where the humidity fluctuates widely, so that the salt can be redissolved and carried into new fissures.
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Answer:
Geologists use radiometric dating to estimate how long ago rocks formed, and to ... as "bracketing" the age of the sedimentary layer in which the fossils occur.
Explanation:
