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.
small chicken farms turned into factories because it was cheaper to
maintain and it also made it cheaper for people to buy eggs. However
this produced a huge problem of what to do with the chicken manure
and this is also a problem amongst other types of livestock as well as well as factories having big oil spills hope this helps sorry didnt know what you wanted for a answer
