Calcium and magnesium dissolved in water are the two most common minerals that make water "hard." The degree of hardness becomes greater as the calcium and magnesium content increases and is related to the concentration of multivalent cations dissolved in the water.
Answer is True video games do reward violent behavior
Viruses because children immune system cannot repeal parasites (no one can) or bacteria that is why we wash or hands. Fungi is not something we can repeal either.
