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:
- Trichinosis
- Bacterial endocarditis
Explanation:
Trichinosis is a parasitic infection that has as its etiological agent the nematode parasites of the genus Trichinella, and the species of greatest interest to human medicine is Trichinella spiralis. One of the first and characteristic symptoms of infection is the swelling of the eyelids, which appears around the 11th day after infection. Subsequently hemorrhages appear in the eye sclera and in the back of the eyes, eye pain and photosensitivity. Then there is the appearance of muscle pain, along with a rash and bleeding below the nails causing dark red vertical lines about 1 to 3 mm long. The pain is intense in the muscles linked to breathing, chewing and swallowing.
Bacterial endocarditis is always associated with a bacteremia that the immune system has failed to counteract. In other words, the presence of bacteria in the bloodstream, which is usually sterile, represents an important cause of bacterial endocarditis, an infection that affects the inner membrane lining the heart and heart valves, especially if they already have a disorder. The disease sets in when bacteria from various parts of the body - from the mouth mainly, but also from the skin, intestines, respiratory tract, and urinary tract - are carried through the bloodstream to a heart valve or other damaged endocardial area where fix it. Among the many symptoms, indicative of the presence of this disease in the body are thin dark red vertical lines about 1 to 3 mm long in the nails.
Answer: There are few ‘laws’ in science. Those ‘laws’ are so named for historical reasons, but they are theoretical in nature. They set out what happens when a theory is applied in practice. A theory is simply the best explanation we have for understanding why some process takes place and predicting what the result will be.
Explanation: Anyone who describes something as “just a theory” does not understand what a theory is. Laws are arbitrary human rules. Theories are severely tested and re-tested explanations of why things happen in the real physical world and can be used to make predictions about outcomes.
Some would say that theories are about why something happens and laws (in science) describe what happens. But this simply makes a scientific ‘law’ a subset of a scientific theory, explaining how to make predictions.
Answer:
22% Thymine
Explanation:
There should be 22% Thymine because of Thymine pairs with Adenine, which on the table is shown to be 22%. (the complementary base pair are always equal). and the same would apply to Guanine (28%) and cytosine (28%).
Proxima Centauri is the nearest star to Earth.
