<span>Birds respond to temperature, food availability, and weather conditions.</span>
Answer:
Positive feedback system increases temperature of the earth surface which is good in a number of ways.
Explanation: For example, due to increase in the temperature of earth surface, melting of ice occurs in the mountainous area of the world. This stored form of water is changed into liquid form and flows down through streams and used by plants and animals. But more increase in temperature causes rise of sea level which is not good for areas near the sea.
The virus needs to speak the molecular language of cells. This is how he manages to dominate and enslave them so that they become factories for new viruses, producing the proteins that the infectious agent requires to assemble its descendants. If this conversation is not fine-tuned, even if the virus has the key and enters, it is doomed to failure.
<h3>Why does a virus lethal to us not infect animals?</h3>
For a virus to be able to enter a cell, it must have the right key. And this key, which are the proteins on the surface of viruses, has to enter the correct lock, the receptors that are on the cell membrane. Cells are actually houses with many different doors and locks. Some viruses have keys that open the lock of any cell and any kind of host, and others do not, so the infection caused by viruses is specific.
With this information, we can conclude that some viruses have keys that open the lock of any cell and any kind of host, and others do not, so the infection caused by viruses is specific.
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When it comes to population evolution and genetics, we cannot fail to cite the Hardy-Weinberg principle which emphasizes that if evolutionary factors such as natural selection, mutation, migration and genetic oscillation do not act on a particular population, the frequencies genotypic proportions will remain constant.
The five requirements for a population to be in Hardy-Weinberg equilibrium are:
- Large-scale breeding population: For a population to be in Hardy-Weinberg equilibrium, it is important that this population is large, as small populations favor genetic drift (unanticipated fluctuations in allele frequencies from one generation to another).
- Random mating: In order for the Hardy-Weinberg equilibrium to occur, it is necessary that the mating occur at random, with no preference for certain groups within the population. In this case, we say that the population is in panmixia, that is, they all mate at random.
- No mutations: Mutations alter the total alleles present in a population (gene pool). Therefore, in a Hardy-Weinberg equilibrium population, no mutations should occur.
- No gene flow: When there is gene flow due to migration or immigration of individuals, some genes may be included or excluded from the population. Thus, in an equilibrium situation, no gene flow occurs.
- Lack of natural selection: For a population to be in Hardy-Weinberg equilibrium, natural selection must not be acting on it. If natural selection acts, some genotypes will be selected, modifying the allelic frequencies of the population.
