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:
Evaporation, Condensation, Precipitation and Collection
Explanation:
I just referred to water cycle on the internet.
Answer:
False
Explanation:
The most specific feature of cardiac muscles is the presence of intercalated discs. Intercalated disc connects the ends of cardiac muscle fibers to one another. The discs have desmosomes and gap junctions. The function of desmosomes is to hold the cardiac fibers together. The gap junctions of cardiac fibers allow muscle action potentials to spread from one cardiac muscle fiber to another. These gap junctions have tubular connexons that form channels and connect the cytosol of adjacent cardiocytes to allow the flow of ions and spread of action potential from one cell to another.
