How do sudden and gradual disturbances affect ecosystems?

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Complete the statements to identify the first two steps of meiosis i. (1 ) the first and longest step of meiosis i is called i. (2)the second step of meiosis i is called i.

Determine if the following statement is true or false. if true, choose true. if false, choose the rewording that is true. according to the law of independent assortment, alleles for each gene are inherited together so that they always stay together. according to the law of independent assortment, offspring express a combination of their parents' traits. according to the law of independent assortment, alleles for a characteristic split during meiosis and combine during fertilization. true according to the law of independent assortment, alleles for each gene are inherited independently so that no two alleles stay together.