Genes involved in production of abnormal red blood cells may have an abnormal sequence of bases (nucleotides), like inherited alteration in the gene for JAK2, a protein with enzymatic activity that's linked to the abnormal production of blood cells.
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A link between cardiometabolic risk factors and race and ethnicity have been studied. It has been found that the rates of cardiometabolic risk factors are higher among ethnic minority populations such as African Americans, Hispanic Americans, and Native Americans.
A model of a globe is a physical model. The limits are that the solar system is too big to be seen all at once. From the Tennessee science textbook, "Many years ago, scientists thought that Earth was the center of the universe and the sky was a blanket that covered the planet. Later through the observation, it was discovered that the objects you see in the sky are the sun, the moon ,stars, and other planets. This new model explained the solar system differently.