Researchers aboard Alvin discovered the presence of hydrothermal vents on the ocean floor.
<span>The question says,' the purpose of the mucus found within the respiratory system is to .............. The correct option is B. The mucus found in the respiratory system function by trapping foreign particles that enter into the lungs especially thorugh the nose during breathing, thus mucus aid in protecting the lungs.</span>
Normally, oxygen from the blood cells supply your muscles with the energy it needs to carry out certain actions. However, when there isn't enough oxygen to support the muscles, it produces lactic acid, or fermentation, to make up for the oxygen. (That's why you get that burn-y feeling whenever you exercise!)
The answer is stabilizing selection.
<span>Sickle-cell anemia is a recessive disorder caused by the presence of two recessive alleles "s", so genotype is "ss". This disorder is characterized by sickle hemoglobin. In an area with malaria, heterozygous individuals "Ss" (with one dominant allele and one recessive allele) have an advantage. These individuals will have both normal and sickle hemoglobin. But pathogen that causes malaria affect only normal hemoglobin, so heterozygous individuals will have half of the hemoglobin resistant to the pathogen and those individuals are resistant to malaria.</span>
Stabilizing selection favors heterozygotes Ss, disruptive selection favors dominant (SS) and recessive (ss) homozygotes, while directional selection favors dominant (SS) or recessive (ss) homozygote. Since in this example, people with genotype Ss (heterozygotes) are in advantage, then this is an example of stabilizing selection.
