A child in the third grade has problems with spelling and reading. She appears very quiet and confused in class. Her teacher has noticed that this girl has trouble following directions. Her mind seems to wander whenever the teacher tells a story or explains something complicated. She is skilled in art and so far has performed well in arithmetic. Which of the following diagnostic procedures is most likely to yield useful findings in this child?

Correct Answer: C

Rationale: Given the child's difficulties with reading, spelling, and following directions, a language evaluation would be most appropriate to assess potential learning disabilities such as dyslexia.

Correct Answer: A

Rationale: Polymyositis is primarily characterized by muscle weakness without the rash seen in dermatomyositis.

Correct Answer: D

Rationale: Beta-thalassemia causes microcytic anemia due to defective hemoglobin production and impaired erythropoiesis.

Correct Answer: C

Rationale: Male gender, rather than female, is a known risk factor for asthma morbidity and mortality, particularly in childhood.

Correct Answer: D

Rationale: Sodium is primarily distributed in extracellular fluid, with a volume of distribution of about 0.6 times total body weight, including interstitial and intravascular compartments.