Human skin color is a polygenic trait, which means that multiple gene loci (with different alleles) are involved in its expression. It has been shown that there more than 350 genetic loci involved in determining skin color. Because of that, there is the enormous number of possible genotypes for the skin color and as a result, the phenotypes vary from the darkest brown to the lightest hues. Different populations have different allele frequencies of genes for human skin color, and the combination of these allele variations brings about complex and continuous variation in skin coloration. Natural skin color can change due to exposure to sunlight (becomes darker) and that is the way it adapts to intense sunlight irradiation (protection against the UV exposure).
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Answer:
picky and typical selection.
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Whenever Mendel performed a cross with pea plants, he carefully categorized and counted the many offspring. Every time Mendel repeated a particular cross, obtained similar results. For example, whenever Mendel crossed two plants that were hybrid for stem height (Tt), about three fourths of the resulting plants were tall and about one fourth were short. Mendel realized that the principles of probability could be used to explain the results of genetic crosses.</span>
<h2>Cell Analogy</h2>
Explanation:
As we see that parents control everything in the house. Similarly,the nucleus controls everything in the cell.
A door is analogous to the cell membrane because it allows people come and go. Similarly,the cell membrane in a cell can allow certain things to enter and exit.
The cytoplasm fills the space in a cell. It is similar to air which is filled everywhere in the house.
- Nuclear membrane: Security guard
The nucleus in a cell is protected by nuclear membrane. The nuclear membrane is analogous to secuity guard. As people in a house are protected by security guard, similarly nucleus is protected by nuclear membrane.
- Endoplasmic reticulum: Hall ways
Endoplasmic reticulum transport things to other places in the cell. It is similar to hallways which help us to reach different places in the house.
The golgi bodies modify,sort and package proteins.
It send them to other parts of the cell when needed.
It is similar to a Car which transports people and can store stuffs.
The mitochondria in a house is analogous to Stove as it breaks down nutrients and turns them into energy. Similarly, the Stove in our house, cooks foods and it is converted into energy when consumed.
The ribosomes are a cell structure that make protein. It is same as a kitchen in our house where people make food or proteins.