What is the main cellular structure involved in respiration?

The image shows embryos of three vertebrate classes

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.

Which describes how weathering and erosion are different? weathering is caused by water. erosion is caused by wind and ice. erosion transports sediments. weathering is a natural process.