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.
A cladogram is a diagram used to represent a hypothetical relationship between groups of animals, called a phylogeny.
In this set of examples the answer is:
D) The lamprey does not have a vertical column
Lampreys have a notochord that remains throughout life, but they have primitive vertebrae made of cartilage. Lampreys have vertebral arches, but nothing resembling the vertebral bodies found in all higher vertebrates. Even the arches are discontinuous, consisting of separate pieces of arch-shaped cartilage around the spinal cord in most parts of the body, changing to long strips of cartilage above and below in the tail region.
The answer is scientific theory. It amalgamates scientific law about objects and events that are widely accepted and tested. Scientific theory rationalizes phenomenon, that is not rigorously understood, through science. Examples of scientific theories today are the special relativity theory of Albert Einstein.
It could have the most direct effect on the amount of mitochondria in cells and also the system of the membrane.
Question 1: B: rapid water drainage
