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Answer:
Sampling
Explanation:
Sampling is a statistical procedure in which a selected number of observations is used to represent the whole observation. When we take an area and we use the population to estimate that of other areas or the whole population, we are simply sampling. Sampling is very important to some specific forms of observations. Sampling can be done randomly or in a systematic way. The goal of sampling is using the part to represent the whole.
Answer:
Option (4)
Explanation:
Seismic P and S waves are generated during an earthquake that has the potential to propagate through the interior of the earth. P waves are also known as the primary waves and they move in a compression and extension way in their direction of propagation. S waves are shear waves. This P waves travel faster than the S waves and can travel in both solid as well as in liquid. Whereas the S wave can travel only through solids. They get absorbed when they reach the core-mantle boundary. These two waves are helpful in determining the epicenter of an earthquake by recording the arrival of these waves.
Hence, the correct answer is option (4).
Earth is mostly made of rock.