Which of the following vitamins is synthesized in the skin?

A. Immunoglobulin G (IgG) is the most abundant antibody in the blood and plays a key role in the body's defense against bacterial and viral infections, but it is not directly involved in allergic reactions.
B. Immunoglobulin M (IgM) is the first antibody produced during an initial immune response, primarily involved in fighting infections, but it does not play a major role in allergic reactions.
C. Immunoglobulin E (IgE) is the antibody most directly involved in allergic reactions. When IgE binds to allergens, it triggers the release of histamine from mast cells, leading to the symptoms of allergies.
D. Immunoglobulin A (IgA) is primarily found in mucosal areas such as the respiratory and gastrointestinal tracts, where it helps prevent infections, but it is not directly involved in allergic responses.

A. Low blood pressure is not typically associated with elevated potassium levels. While severe hyperkalemia can impact the cardiovascular system, it does not directly cause low blood pressure as a primary symptom.

B. Rapid respirations are generally associated with conditions like acidosis or respiratory distress but are not a primary consequence of elevated potassium levels.

C. Elevated potassium levels are not typically associated with constipation. In fact, hyperkalemia can cause gastrointestinal symptoms such as nausea or abdominal cramping, but constipation is more commonly linked to conditions like low potassium levels (hypokalemia).

D. Elevated potassium levels, or hyperkalemia, can cause cardiac irregularities such as arrhythmias, which can be life-threatening if not managed promptly. This is the most significant and direct effect of high potassium levels in the blood.