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:
because the sun shines on it when it rotates. depending on where the sun rises and setes makes the lunar phases. Such as full moon. New moon.
Explanation:
To make a compound more stable at storage temperature.
Cell-tissue-organ-organ system-organism
