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.
Haploid refers to the presence of a single set of chromosomes in an organism's cells.
Answer:
The correct answer is the endocrine system.
Explanation:
The sympathetic division of the autonomic nervous system and the endocrine system are the two prime systems that take part in the stress response.
At the time of acute or chronic stress, the endocrine system first makes the hypothalamus to discharge CRH or corticotropin-releasing hormone into the bloodstream. The release of CRH further makes the anterior pituitary to discharge ACTH or adrenocorticotropic hormone into the blood. This further stimulates the adrenal cortex to discharge cortisol, that is, one of the glucocorticoid hormone into the bloodstream.
The cortisol finally makes the organs and tissues present within the body to effectively cope up with the initial stress stimulus.
The number of weight gained in pregnancy should be different based on the BMI. Assuming Sadie BMI is 25-29.9kg/m2 then the normal weight gain for single pregnancy would be 15 to 25lbs.
Higher BMI will cause the normal weight gain become lower. For BMI >30kg/m2 normal weight gain would be 11-20lbs
