Answer:
Seafloor spreading occurs along mid-ocean ridges—large mountain ranges rising from the ocean floor. The Mid-Atlantic Ridge, for instance, separates the North American plate from the Eurasian plate, and the South American plate from the African plate.
Explanation:
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This is because not all genes are expressed at the same time, so not all the proteins are present at a certain moment. The mechanisms that cell uses to control gene expression are called regulation of the gene expression. Thanks to regulation of the genes, cells have the ability to increase or decrease the production of specific gene products such as proteins. This property is important for the adaptability of an organism because it allows the cell to express protein when needed.
Answer:
'Cross experiments done by Morgan, illustrating the X-inheritance link of a mutation Thomas Hunt Morgan moved intensely in a program of breeding and crossing miles of fruit flies at New York University in a room that was renamed the Fourth of the Flies. He tried to mutate the flies with various means (X-rays, centrifuges, etc.) .The fruit fly which has 4 pairs of chromosomes. One of those pairs was identified as containing X and Y sex chromosomes. He applied Mendelian principles in flies. Morgan's inheritance study demonstrated inheritance linked to sex, and is one of the first evidences that confirm the chromosomal theory of cross-based inheritance. In 1909, Morgan detected a fruit fly (Drosophila melanogaster) with a strange mutation which he called "white eyes", due to the coloration of his eyes (contrary to normal, which is red). Analyzing this fly under the microscope Morgan discovered that it was a male, and could use it as a stallion so that he could observe how the new characteristic of white eyes would pass from generation to generation.All the offspring of this cross will have red eyes, which He made Morgan suspect that something strange had happened, since the color of the father's eyes could not have disappeared. He decided to take a couple of "daughters flies" and cross them together, just to see what happened. Morgan's surprise was very great, observing that among the "granddaughters" flies only males had white eyes. The problem then was to explain what had happened during the hereditary transmission for the color of the white eyes only the males possessed. .
