<span>The best and most correct answer among the choices provided by the question is the first choice. A decrease on the pine trees would decrease the number of the woodpeckers. <span>I hope my answer has come to your help. God bless and have a nice day ahead</span></span><span>
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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:
Blood plasma:
55% composition of blood contains blood plasma. The plasma contains various proteins and coagulating factors. This mainly include the fluid portion of the blood. Plasma is a straw colored liquid that contains antibodies as well as serum.
Formed elements:
45% composition of blood contains formed element. The formed elements contain RBCs, WBCs and platelets. This mainly include the cells portion of the blood. Formed elements is red color or no color depending on the pigment present in the cells of formed element.
