Answer:
four layers
Most rainforests are structured in four layers: emergent, canopy, understory, and forest floor.
Explanation:
Answer:
Homeostasis refer to as the maintainence of equillibrium within the body. Endocrine systems play a major role in maintainence of equillibrium. The hormones released are continuously inactivated by negative feeback system to maintain homeostsis.
Explanation:
Homeostasis in a body is refered as a dynamic equillibrium which constantly changes. Feedback regulation systems maintain homeosatsis.
The release of hormones into the blood is controlled by a stimulus. A stimulus can increase or decrease the release of hormones.The response to a stimulus changes the internal conditions and may itself become a new stimulus. This self-adjusting mechanism is called feedback regulation.
There are two types of feedback systems.
Negative feedback occurs when the response to a stimulus reduces the original stimulus. Positive feedback occurs when the response to a stimulus increases the original stimulus.
If the hormones released are not controlled by these feedback systems, enormous amount of hormones will change the whole internal enviornment of the body ,hence, equillibrium will be disturbed and result in death of cells and death of an indivisual.
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.
