I just took this test and I put "the top carnivore in a FOOD WEB" and got it right. I hope this helps. :)
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Typical cervical vertebrae have several features distinct from those typical of thoracic or lumbar vertebrae. The most notable distinction is the presence of one foramen, in each transverse process. These transverse foramina encircle the vertebral arteries and veins.
The placenta forms at 8 weeks, and develop for 6 weeks. hope this helps
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.