It would be completely false to say that both internal and external environments can modify or alter a gene. The correct option among the two options that are given in the question is the second option or the last option. I hope that this answer has come to your great help.
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.
A. manufacture of a strand of rna complementary to a strand of dna
Answer:
False
Kentucky bluegrass and zoysia
perennial ryegrass
hope it helps have a nice day
