Answer:
Selection is a directional process that leads to an increase or a decrease in the frequency of genes or genotypes. Selection is the process that increases the frequencies of plant resistance alleles in natural ecosystems through coevolution, and it is the process that increases the frequencies of virulence alleles in agricultural ecosystems during boom and bust cycles.
Selection occurs in response to a specific environmental factor. It is a central topic of population and evolutionary biology. The consequence of natural selection on the genetic structure and evolution of organisms is complicated. Natural selection can decrease the genetic variation in populations of organisms by selecting for or against a specific gene or gene combination (leading to directional selection). It can increase the genetic variation in populations by selecting for or against several genes or gene combinations (leading to disruptive selection or balancing selection). Natural selection might lead to speciation through the accumulation of adaptive genetic differences among reproductively isolated populations. Selection can also prevent speciation by homogenizing the population genetic structure across all locations.
Selection in plant pathology is mainly considered in the framework of gene-for-gene coevolution. Plant pathologists often think in terms of Van der Plank and his concept of "stabilizing selection" that would operate against pathogen strains with unnecessary virulence. As we will see shortly, Van der Plank used the wrong term, as he was actually referring to directional selection against unneeded virulence alleles.
Answer:
the vaccine causes the immune system to produce antibodies to the virus that causes the measles
Answer:
<u>A. red blood cells containing malaria</u>
Explanation:
Malaria is a disease-causing pathogen in humans. It is caused by species of the parasite <em>Plasmodium sp.</em><em>,</em> which is transmitted as sporozoites by the Anopheles mosquito upon biting the host. These travel through the bloodstream to the liver where they mature into merozoites. These reenter the bloodstream and mature into trophozoites and schizonts that produce more merozoites.
When they multiply within the red blood cell, they <u>burst the red blood cell open</u>, and go on to infect other cells. This infection's symptoms are cyclic and include high fever, chills and other flu-like symptoms.
Malaria is a deadly illness, causing harm to its hosts, and in many cases death. <u>Thus, this cannot be defined as symbiosis, which is typically beneficial to both organisms.</u>
A researcher is interested in screening for p-elements inserted into a region on chromosome 3. to produce new insertions, she crosses females homozygous for a miniwhite + p-element on the x chromosome with males homozygous for immobilized transposase on chromosome 2. what genotype will the f1 male flies have? (note that a "+" indicates a wild-type chromosome without the transposase locus or the p {miniwhite +} insertion. the x /y chromosomes are listed first, followed by the second
Answer:
Parts of a homogeneous mixture are evenly mixed
Explanation:
A homogenous mixture is a mixture in which two or more substances are evenly mixed but not bonded together.
This is a homogeneous mixture, or a solution.
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