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.
Learn more about Sickle-cell anemia on
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Answer:
Explanation:
Cerebellum is a leaf-like structure that is a part of the hind brain and is responsible for:
- coordinating skeletal muscle movements.
- controls movements, posture and balance.
- involved in learning too.
So, if the cerebellum of the brain is affected/injured, a person can have difficulty in keeping their body in a balanced position, coordinate voluntary movements of skeletal muscles and learning.
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Hope this helped!
<h3>~AH1807</h3>
Forest fires actually help the environment, they remove plants and trees that are useless and leave space for new plants and trees to grow. After 26 years after the fire, the forest will start to grow again and will be green once again.
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The autotrophs are the primary producer in the food chain and they are the ones who initiate the food chain. They produce food by using sunlight or sometimes chemical energy or reactions. They primarily use carbon dioxide, sunlight and water to form sugars or carbohydrates which become their energy source. They use the process of photosynthesis or chemosynthesis to generate food. Examples of autotrophs are green plants, green algae, bacteria.
Heterotrophs cannot make their food via sunlight or other inorganic sources and hence are dependent on the autotrophs or other animals. The heterotrophs have been ranked as secondary and tertiary consumers and cannot be producers. They consume the organic products made by autotrophs to obtain energy for various metabolic and biological activities. The heterotrophs can be herbivore, carnivore, fungi, parasitic plants.
Some are photo-hetrotrophs, who use light as energy but cannot use carbon dioxide as the carbon source since they cannot fix the carbon like autotrophs.
Answer:
In C4 photosynthesis, where a four-carbon compound is produced, unique leaf anatomy allows carbon dioxide to concentrate in 'bundle sheath' cells around Rubisco. This structure delivers carbon dioxide straight to Rubisco, effectively removing its contact with oxygen and the need for photorespiration
