Answer:
Explanation:
The sickle cell allele is recessive. Hence, in order for any child of the couple to have sickle cell anemia, such a child will have to inherit an affected allele each from the two parents. This means that both the father and the mother must have affected alleles in their genotypes. In other words, two sickle cell alleles are required for the abnormality to manifest.
Let us assume that the sickle cell allele is represented by S and the normal allele is represented by A.
Now, it is established that the mother has sickle cell anemia, her genotype would be SS. The father does not have sickle cell, his genotype can either be AA or AS.
Assuming the genotype of the father is AA:
SS x AA
AS AS AS AS
<em>All the children would be normal in this case.</em>
Assuming that the genotype of the father is AS
SS x AS
AS SS AS SS
<em>50% of the children would have sickle cell while the remaining 50% would be normal.</em>
<u>Therefore, in order to produce children with sickle cell, the father has to be AS, otherwise, he has to be AA.</u>
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c. Birth rates are high
Explanation:
A wide base in the population pyramid shows that there is a large population of young people with high fertility rate or birth rate and high death rate.
From the graph, it can also be concluded that narrow tip at the top shows that lesser older people are in the population.
This pyramid shown in the diagram is a triangular age pyramid. In this type of pyramid the pre-reproductive individuals are high reproductive individual are moderate and non-reproducing individual is less. In such pyramid we find population grows.
Suppose in a family of ten 6 are pre-reproductive, 2 moderate reproductive and 2 post-reproductive. We will see the in the course of moderate and post-reproductive will die and those six of pre-reproducing age will increase the population.
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A mass movement is movements of masses of bodies of soil, bed rock, rock, debris, soil etc. which usually occur along steep-sided hills and mountains because of the pull of gravity
Dna damage can occur as a result of exposure to chemicals or ultraviolet radiation. This is what happens during nucleotide excision repair of damaged dna. A multienzyme complex crosses the DNA in search of distortions in the double helix, once located, the phosphate skeleton of the affected chain is cut on both sides of the altered region, a helicase eliminates the oligonucleotide resulting from digestion, the "Gap" "is filled with a DNA polymerase and a ligase.
