No, the sickle-cell anemia allele won't be eliminated by natural selection.
Sickle-cell anemia trait is controlled by a single gene and the allele (S) for sickle-cell anemia is a harmful autosomal recessive.
It is caused by a mutation in the normal allele (A) for hemoglobin (a protein on red blood cells).
Heterozygotes (AS) with the sickle-cell allele are resistant to malaria, a deadly tropical disease. It is common in many African populations.
In these areas, (S) carriers have been naturally selected, because their red blood cells, containing some abnormal hemoglobin, tend to be in sickle shape when they are infected by the malarial parasite.
Therefore, they are more likely to survive and reproduce. This keeps the S allele in the gene pool.
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Answer:
A dam that could allow fish to still pass through is a fishway/fish pass its a "fish ladder" that is structured on or around artificial or natural barriers to allow for fishes natural migration and the movement for potamodromous species.
I think the correct answer from the choices listed above is option D. Destruction of tundra vegetation will likely result in melting of the permafrost. The tundra ecosystem is extremely sensitive to disturbance with little ability to restore itself. The melting of the permafrost will <span>cause the collapse of ground and loss of soil. </span>
2NH3 is equivalent to N2 + H6 since the 2 at the beginning gets distributed to both atoms. Knowing this you can rewite the equation as
H2 + N2 = H6 + N2
The N2 can cancel out leaving
H2 = H6
You now have to ask ‘2 times what equals 6?’ The answer is obviously 3 at this point.
Answer: C. 3
No because he/she will surley be put under the same pressure
