Think of it this way:
DNA inside cells store all the genetic information on a person's looks, eye colour, hair colour etc. It makes them unique. The analogy of being like books in a library basically suggests that in a library there is so much information and every book is different with different knowledge... That's basically what DNA is; millions of different information things.
Answer: C. The C horizon is very deep.
Horizons are the layers of soil develops as a result of soil formation. Horizon lies parallel to the earth surface. Each horizon differs from the other on the basis of amount or organic matter present, color of the soil, texture of soil and other components making up horizon, and amount and type of minerals present in the soil.
C horizon is the horizon that lies deeper region of the collective soil horizon. It consist of unweathered or partially weathered rocks or their aggregates. Therefore, it retains the original chemical composition of the parent rock. This results in the higher mineral content as compared to other horizons. This horizon also lacks the organic matter as no or very little decomposition activity of plant and animal matter takes place. Therefore, color of soil in this horizon in the absence of organic matter remains light.
Hence, a sample of soil from a C horizon is light brown in color and has a high content of a mineral called feldspar is because of the fact that the C horizon is very deep.
Multiple things cause the migration of people.
Economic issues arise:
People run out of jobs and opportunities
(BIGGEST REASON)
Cultural reasons:
Forced intentional migration had occurred in the past on accounts of slavery and political instability
Safety:
More popular reason now is because of war or fights with other countries, the people want to keep their family safe so they move them or move with them
Hope this helped