Answer:
Vestigial structures
Explanation:
Vestigial structuresserve little or no present purpose for an organism. The human tail, which is reduced to the tailbone during development, is one example.
Answer:
Increased frequency of the allele for sickle cell anemia
Explanation:
Sickle cell anemia is fatal in homozygous genotype. The homozygous genotype having two copies of the allele for sickle cell anemia is not favored by natural selection due to its reduced survival success.
However, the heterozygous genotype for sickle cell anemia with one allele for the disease exhibit malaria resistant. The presence of one allele is not fatal for the organisms as the presence of one normal allele ensures the formation of some normal hemoglobin protein and RBCs to support the oxygen delivery to the body parts.
The increased survival success of heterozygous genotype in malaria-prone regions allowed their natural selection. This increased the frequency of allele for the sickle cell anemia in the gene pool of the local population and increased the frequency of heterozygous dominant genotype.
It acts as a framework inside the endoplasmic reticulum and keeps it from collapsing . it helps keep the organelles in place and directs their movement as needed . it keeps the DNA safely enclosed in the nucleus and holds the nucleus together . it provides anchoring places for the cell cytoplasm and help it move molecules . maybe that help :)
