Why is the federal income tax a progressive tax? @whpalmer4 @thomaster @iambatman @linda3 @dollyacquah @ashleyisakitty @kewlgeek555?

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.

Study the diagram of a cell. which structure is found only in plant cells and functions in the process of photosynthesis? w x y z

Acertain species of fish can have either long or short fins. the allele for long fins is dominant over the allele for short fins. a heterozygous, long-finned fish is crossed with a homozygous, short-finned fish. of the offspring, will have long fins and be , and will have short fins and be .