The answer is letter
D.
<span>
Economists often use
the aggregate supply and demand model to reflect the total amount of goods and
services required at all possible price levels during a specific period. It
reflects the overall price of foods and services in an economy for a given
period and is often illustrated with the supply-demand curve. This shows the
relationship between price levels and quantity of output that a particular firm
is willing to provide to the general public.</span>
I believe it's B. BRCA1 and BRCA2.
The genetic code is carried out by the Deoxyribonucleus acid DNA molecule in most organisms. Most of the viruses have RNA as their genetic material which codes genetic information.
A) A textbook definition would be that genetic drift is: a random change in allele frequency caused by a series of chance occurences that cause an allele to become more or less common in a population. In layman's terms, this means that genetic drift happens when luck makes the genetic pool of the population to deviate from what is expected.
B) The cause for this genetic drift is the aformentioned couple. Because amish communities are small and they select partners from their community, having even a couple of carriers of alleles in a community can make the allele freuency much larger than expected; for example, if the community was 100 persons, the percentage would be in the order of 1%, still much larger than the general population. Thus, the cause here is that a small population had a couple of carriers.
C) Sexual reproduction leads to a mixing of alleles from both mother and father and helps diversity. When a population is isolated, the gene pool is fixed and no new genes can come in, reducing diversity. Also some people that have an allele might die, hitting diversity even more. Finally, having a small population creates a strong pressure in some circumstances that leads to elimination of some traits and diversity.
