Answer:
here.
Explanation:
Due to the prevalence of malaria in Africa, the allele for sickle cell anemia (HbS) provides a selective advantage. That's why it remains in the population.
A normal African person (HbAHbA), with normal haemoglobin, will not die of anemia, but will die of malaria.
An African person with sickle cell anemia (HbSHbS), with abnormal haemoglobin, will die of anemia.
A heterozygous African person (HbAHbS), with half of his red blood cells (RBCs) being normal and the other half being sickle-shaped, will neither die from anemia, nor malaria since the plasmodium will be incapable of completing its life cycle in the abnormal RBCs.
Thus heterozygous African people will grow, reproduce and pass on the HbS allele to the next generations.
Answer:
Option (1), (2) and (3).
Explanation:
Doppler effect may be defined as the change in wavelength due to the the movement of sound or radiowaves travels from the object. The frequency remains same if the distance between the receiver and sender's electromagnetic wave distance is same.
Doppler effect helps to learn about the universe behavior. Hubble used the Doppler effect to study the velocity of galaxy. The galaxy motion can be indicated by the wavelength and light.
Thus, the correct answer is option (1), (2) and (3).
Plastics clearly constitute an important component of the range of materials used in modern society. Almost all aspects of daily life involve plastics or rubber in some form or the other. ... Owing to their light weight, plastics reduce transportation costs and, therefore, atmospheric carbon dioxide emissions./Plastic is durable and provides protection from contaminants and the elements.
it dates back to the Precambrian era
