Aerobic or anaerobic atp exchange <span />
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. a disease
Explanation:
Pathogens are disease-causing organisms. For example, some bacteria and viruses are pathogens for different species.
Therefore, a tree with pathogens present is likely to have a disease. Different pathogens affect different trees. Examples include Anthracnose
, which is caused by a fungus
The statement that best compares gymnosperms and angiosperms is : A. Both reproduce sexually, but gymnosperms contain only xylem and angiosperms contain xylem and phloem.
Gymnosperms produce exposed seeds, not enclosed in fruit whilst Angiosperms have Fruits, flowers, and endosperms as defining characteristics.
