The contracting and relaxing of muscle is regulated by the amount of calcium present in the cells of muscle fibers. these cells must be able to move the calcium ions from areas with low concentrations to areas with high concentrations. what process would be necessary for this movement to occur?

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.

amber has allowed scientists to study dna that has been preserved over millions of years.

the correct answer: the index of refraction of the second medium is lower i tried this persons answer and it was wrong this person is lying