Answer:
Because natural selection selects for it. Thus it persists.
Explanation:
You have to understand heterozygote advantage. Basically, it's where heterozygotes have an advantage over homozygotes. In the case of sickle cell disease, heterozygotes have an advantage, and natural selection favors whatever is advantageous. Thus, because heterozygotes each have one recessive sickle-cell allele, as natural selection favors the heterozygotes, the recessive sickle-cell allele persists and remains in the gene pool.
Answer:the virus seems to keep changing and adapting
Explanation:
For example they have found that it now attacks your kidneys heavily causing failure when in the beginning it did not
Explanation:
a barometer is one of the most common instrument used for weather forecasting and measuring tornadoes.
The nucleus controls everything in a cell
