they are caused by mutation. the best example of it are human blood groups.
Answer:
Makali may produce only small amounts of a non-mutated (wild-type) GALT enzyme.
Makali may have normal amounts of GALT, but the enzyme may be mutated.
Explanation:
Makali is lactose intolerant because of his ancestry. Because of this he is not able to digest any lactose which indirectly protected him from galactosemia. Thus he must avoid consuming galactose. He has a low GALT or galactose 1‑phosphate uridylyltransferase activity. He has a normal amount of GALT and may produce only small amounts.
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.
Answer: Its smaller jaw bone
Explanation: Just look at the picture
Gravitational potential energy