Answer:
https://phys.org/news/2009-05-bird-songs-environment.html
Explanation:
Answer:
a. vitamin d and vitamin b12
Explanation:
Vitamins are groups of organic compounds that are essential in small quantities for healthy human growth, metabolism, development, and body function. Vitamins are found in plants and animal foods or sometimes produced synthetically. Deficiencies of specific vitamins produce specific disorders. Vitamin d and vitamin b12 are important vitamins that the body needs. The body produces vitamin D when the skin is exposed to sunlight and it is very essential for strong bones, while vitamin b12 is naturally present in meats. Deficiency of vitamin d in the body can result in bone problems (including teeth) and it has also been linked to depression. Vitamin b12 deficiency can also affect mental functions by causing disorientation, memory loss, depression and confusion.
From the question, the elderly woman may be developing a deficiency of vitamin d and vitamin b12.
Answer:
when fertilization takes place, the half of the chromosomes from the egg combine with the half of the chromosomes from the sperm to form a full 23 pairs of chromosomes which contain the genes of the offspring.
<span>The movement of alleles from one population to another is called gene flow. Other alleles will likely increase in frequency and become fixed. These changes in allele frequencies that are due to chance are called genetic drift. Genetic drift causes a loss of genetic diversity in a population.</span>
Answer:
At meiosis II in the mother
Explanation:
Both the parents have normal vision but both the sons are colorblind. Since colorblindness is X linked recessive disorder, the sons have obtained the allele for colorblindness from mother. This makes the mother carrier for colorblindness. The genotype of the mother is X^cX. The young man with Klinefelter syndrome is colorblind which means that he is homozygous recessive for the allele of colorblindness. His genotype is X^cX^cY. Since this man has obtained two copies of the allele of colorblindness, the mother must have experienced nondisjunction at meiosis II during gamete formation.
Anaphase-II of meiosis II separates and segregates the sister chromatids (now called daughter chromosomes) to opposite poles. Failure of segregation of two copies of X^c chromosome of mother to opposite poles and their distribution to the same egg cell resulted in the formation of an egg with two copies of X^c chromosome. Fertilization of this egg with a sperm carrying "Y" chromosome as sex chromosome resulted in a zygote with X^cX^cY that developed into the man with Klinefelter syndrome and colorblindness.
