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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In Earthquake testing, the engineers are using the world largest shake tables to test new construction methods for buildings in the areas prone to the earthquake.
<u>Explanation:</u>
They believed that they have the devised a system to build the taller wood-frame buildings that can still safely withstand even very powerful tremors. To withstand the collapse, the buildings need to redistribute the forces that travel through them during a seismic event.
Shear wells, cross braces, diaphragm, and moment-resisting frame are the central reinforcing the building. Shear wells are the technology of the useful building. That helpful to transfer the earthquake forces.
<span>Some mutations don't have any noticeable effect on the phenotype of an organism. This can happen in many situations: perhaps the mutation occurs in a stretch of DNA with no function, or perhaps the mutation occurs in a protein-coding region, but ends up not affecting the amino acid sequence of the protein.</span>
Answer:
The correct answer is D. proliferation and differentiation.
Explanation:
Primary immune response occurs due to the first exposure of an antigen to the immune system. The primary immune response is generally delayed by many days because it takes time for B and T cells to become cloned and to proliferate and differentiate.
Then after several days of proliferation and differentiation of activated T and B cells, T cells become effector T cells and B cell becomes plasma cells which then eliminates the antigen. Memory B and T cells are also produced during this process which helps in generating a quick immune response during the second and subsequent exposure of that antigen.
So the correct answer is D. proliferation and differentiation.
In terms of function, bird wings are used to flap transversely, whereas butterfly wings are used to flap laterally. In terms of structure, bird wings are filled with hollow bones for easier flight, whereas butterfly wings are structured by scales and tiny hairs.
