[" 48.Which of the following statements in false? "],[" (a) Ca "2+" ions are not important in maintaining the regular beating of the heart."],[" (b) "Mg^(2+)" ions are important in the green parts of plants "],[" (c) "Mg^(2+)" ions form a complex with ATP "],[" (d) "Ca^(2+)" ions are important in blood clotting."]