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Together,the number of protons and the number of neutrons determine an elements isotopes have slightly different mass numbers, the atomic mass is calculated by obtaining the mean of the mass numbers for its isotopes.
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The hormone calcitonin, which is produced by the parafollicular or C cells of the thyroid, has the opposite effect on blood calcium levels as does PTH. I hope this helps! : )
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Answer:
Rivers often start from the mountain streams and contain high amounts of oxygen. Rivers and streams grow larger as these waters merge. Rivers pick up sediments from the land as they flow. Lakes support many varieties of organisms, including plants in shallow,