Answer:
Chitin is a fibrous material made up of polysaccharides that is found in the exoskeletons of arthropods and the cell walls of fungus. Chitin is an important biopolymer found in nature. Fungi, arthropods, and nematodes are the principal producers. In insects, it acts as a scaffold, supporting the epidermis and trachea cuticles, as well as the peritrophic matrices that line the gut epithelium.
Explanation:
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A transfer of energy in practice means that one organism eats the other organism, so here we have to ask whether the first organism is eaten by the second.
A. from rabbits to green plants
Plants don't eat rabbits so -no!
B. from weasels to eagles
-this is the correct answer! Eagles do prey on weasels and eat them whenever they can
C. from eagles to rabbits
Rabbits don't eat eagles -so, no!
D. from green plants to weasels
Weasels are predators so they don't eat plants!
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.
Interphase and cytokinesis are preparing the cell to go through mitosis and multiply