More than likely mutation
With shorter necks, giraffe ancestors could not reach food-containing branches on tall trees. This resulted in the directional selection of giraffes with longer necks.
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Why is choosing a direction necessary? </h3>
It nearly appears obvious that the giraffe's long neck developed as a result of a lack of food in the lower branches of trees. The giraffe has a significant advantage because it is taller than any other mammal and can feed where few others can.
When compared to modern giraffes, the giraffe's ancient predecessors had a shorter neck. The plants that were lying at a higher level were inaccessible to them. Giraffe phenotypes have changed in various ways, and now have long necks to reach vegetation that is higher up. The extreme form is chosen above other features in directional selection. It was decided to choose the long-necked giraffe over the short-necked.
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Answer:
It means one trait does not influence the expression of the other. Example is given in the explanation section.
Explanation:
A trait is the phenotypic characteristics an organism possesses. It is determined and controlled by genes. According to Mendel, an organism receives two forms of every gene called ALLELE. Each allele of a gene encodes a different trait.
Mendel, in his law of independent assortment stated that the inheritance of a trait encoded by the alleles of one gene does not influence the inheritance of another trait encoded by the alleles of another gene. A trait is said to be independent of another if it doesn't influence the expression of the other trait.
An example is the seed colour and seed shape trait in a plant. The seed colour trait is encoded by a certain gene and its expression and inheritance is independent of the seed shape trait encoded by another gene.
<u>Stem cell </u>research has the potential to significantly impact the development of disease-modifying treatments for Parkinson’s disease with considerable progress made in creating dopamine-progressing cells.
Explanation:
Parkinson’s disease, a neurodegenerative disease, leads to reduction of dopamine (a neurochemical messenger which carries messages involving thinking and body movements to brain) in the body because the disease will target and kill dopamine-producing nerve cells (neurons). This leads to loss of movement and thinking abilities which are activated by dopamine.
Stem cells research is done to study about the prospects of stem cells in stem cell therapy for Parkinson’s patients as a viable source of new dopamine nerve cells. Research has been involved in growing stem cells to replace or regenerate dopamine-producing nerve cells by using embryonic stem cells or induced pluripotent stem cells as a treatment modality in Parkinson’s disease.
