B!!!!!!!!!!!!!!!!!!!!!!!!!!
After hundreds or even thousands of generations both alleles for sickle cell anemia are still common in those of African ancestry. This is supported by two mechanisms: heterozygote advantage and gene flow.
Heterozygote advantage
When an allele is said to be heterozygous, it is carrying one copy of a gene. For example if one carries a copy of sickle cell allele, it will stay in the population even after many generations — natural selection will not be able to remove it and it will be passed on through generations. So, having one copy of that allele is advantageous but not deleterious.
Gene flow
With humans migrating throughout the different parts of the world, sickle cell allele is passed from one person to another or in different populations. It is actually advantageous to have one copy of this allele especially if there’s malaria in the area, which the allele is resistant.
Answer:
Hi What is the perimeter of this polygon?
A
−11f−8d−11
B
−f+5d−3d−3f
C
f−3+6d
D
2d−4fWhat is the perimeter of this polygon?
A
−11f−8d−11
B
−f+5d−3d−3f
C
f−3+6d
D
2d−4f
Explanation:
Answer:
Evolution is a scientific theory used by biologists. It explains how living things change over a long time, and how they have come to be the way they are. ... It is known that living things have changed over time, because their remains can be seen in the rocks. These remains are called 'fossils'.
