1. What is the difference between a rill and a gully

They said i have got a sign of tuberculosis what should i do

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.

The bacteria found in soil is usually harmful and measures are taken to remove any traces of microorganisms. true or false