Lipids are hydrophobic is the answer you are looking for.
Answer:
- They are made of denser objects, which can condense at relatively high temperatures;
- They are made of heavier elements, which have a stronger gravitational attraction to the Sun;
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.
