I think the answer is B but I'm not sure sorry
The sun is not a living thing. It is made up of gases, such as hydrogen and helium, rather than living cells, which are present in all forms of life
Answer:
major public health concern. Annually, flu causes illness in a substantial proportion of the U.S. population and may result in serious complications, including events leading to hospitalization and death. Influenza viruses are highly unpredictable.Mar 8, 2018
Answer:
directional selection, stabilizing selection
Explanation:
Directional selection is a type of natural selection that favors one extreme phenotype over other phenotypes, thereby modifying allele frequency in the direction of the favored phenotype. This type of positive selection is the main cause of phenotypic diversification. In the USA, the environment created a selection pressure that favored individuals that don't have the defective sickle-cell allele, thereby reducing its frequency in this population. Stabilizing selection, also known as balancing selection, is a type of natural selection where the most common phenotype is selected in the population, thus predominating in future generations. In equatorial Africa, the defective sickle-cell allele is present in a high frequency because individuals that are heterozygous for this allele are less susceptible to malaria, and therefore balancing selection should maintain this allele in the African population.