Which statement regarding serum magnesium (Mg ++) is true? (Select all that apply.) Alcohol-related diseases frequently cause low Mg+ levels. Vomiting is not generally seen as a major cause of Mg+ loss. Mg++ levels present similarly to calcium (Ca++) levels in the blood. Mg+ deficiencies often result in low serum potassium (K+) levels. Mg+ deficiencies must be treated before potassium (K+) deficiencies.