Attention Deficit Hyperactivity Disorder (ADHD) id a disorder characterized by:

A) Heat intolerance.

Explanation: This statement is true. Heat intolerance is a common symptom of hyperthyroidism, including Graves' disease. People with hyperthyroidism often have an overactive thyroid gland that produces an excessive amount of thyroid hormones. This can lead to an increased metabolic rate, which in turn makes them sensitive to heat. They may feel excessively warm, sweat more than usual, and have difficulty tolerating hot weather.

B) Weight gain.

Explanation: This statement is false. Weight gain is not a typical finding in Graves' disease or hyperthyroidism. In fact, one of the hallmark symptoms of hyperthyroidism is unexplained weight loss despite increased appetite. The elevated levels of thyroid hormones cause an increase in metabolism, leading to weight loss.

C) Bradycardia.

Explanation: This statement is false. Bradycardia refers to an abnormally slow heart rate, typically below 60 beats per minute. In hyperthyroidism, the heart rate is often elevated rather than slowed down. The excessive thyroid hormones can lead to an increased heart rate (tachycardia) and palpitations. It's important to note that if the question were about hypothyroidism (underactive thyroid), bradycardia might be more relevant.

D) Lethargy.

Explanation: This statement is false. Lethargy, or a state of extreme tiredness and lack of energy, is more commonly associated with hypothyroidism (underactive thyroid) rather than hyperthyroidism. Hyperthyroidism usually leads to symptoms of increased energy, restlessness, and hyperactivity due to the elevated metabolic rate caused by excess thyroid hormones.

A) Absence of proteinuria:

Chronic glomerulonephritis often involves damage to the glomeruli in the kidneys, which can lead to the leakage of protein into the urine, resulting in proteinuria. The absence of proteinuria would be an unexpected finding in a patient with chronic glomerulonephritis. Therefore, this choice is incorrect.

B) Serum phosphorus 4.0 mg/dL (within expected reference range):

Serum phosphorus levels within the expected reference range are not directly related to chronic glomerulonephritis. While abnormalities in electrolyte levels might occur due to kidney dysfunction, serum phosphorus within the normal range is not a hallmark finding of glomerulonephritis. Therefore, this choice is incorrect.

C) Serum potassium 3.8 mEq/L (within the expected reference range):

Similar to serum phosphorus, serum potassium levels within the normal range are not specific to chronic glomerulonephritis. Kidney dysfunction can indeed affect electrolyte levels, but a serum potassium level within the normal range doesn't provide specific information about glomerulonephritis. Therefore, this choice is incorrect.

D) BUN 50 mg/dL (elevated):

Blood Urea Nitrogen (BUN) is a waste product that is filtered by the kidneys. Elevated BUN levels indicate impaired kidney function, as the kidneys are less efficient at filtering and excreting waste products. Chronic glomerulonephritis can lead to progressive kidney damage, which can result in elevated BUN levels due to decreased filtration and clearance. Therefore, an elevated BUN level is an expected finding in a patient with chronic glomerulonephritis.