Microtubules are hollow tubes of protein that maintain cell shape and permit movement of cell organelles.
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Answer:
Melanin
Explanation:
Some races that are genetically programmed in such a way that the color changes according to the ambient temperature, as is the case of the Siamese cat.
Siamese cats has a gene that produces melanin (gives hair color) depending on body temperature.
This gene stops painting color when the average temperature of cats is exceeded. This absence of color (that is, white cat) causes several curiosities to occur:
1) Siamese cats that are subjected to higher temperatures, for example in summer, can develop a partial albinism.
2) Siamese babies are usually born very white, because in the mother's womb the temperature is warm. As they come in contact with the outside, the gene begins to color their fur.
3) Cat's body is colder around the ears, legs and tail. For that reason they are usually the most colored areas of the Siamese.
<span>The first two tenets of the Cell theory were postulated by Schleiden and Schwann at the first half of the 19th century. Those tenets are that "all organisms are composed of one or more cells" and that "the cell is the basic unit of life". In 1855, Rudolf Virchow added the third tenet "Omnis cellula e cellula" which means that "all cells come from cells". In other words, cells can be formed only in the division of other cells.</span>
