A 3-year-old child born at 24 weeks gestation has a history of prolonged mechanical ventilation and oxygen therapy. The child now presents with recurrent wheezing and exercise intolerance. What is the most likely underlying diagnosis?

A 78-year-old man presents with worsening exertional dyspnea and occasional dizziness. He has a history of long-standing hypertension. Echocardiography shows concentric left ventricular hypertrophy with preserved ejection fraction. What is the most likely cause of his symptoms?

Which congenital heart defect is characterized by abnormal communication between the right and left atria, resulting in excessive pulmonary blood flow and potential right-sided volume overload?

A patient with severe kyphoscoliosis presents with progressive shortness of breath and reduced lung volumes. What is the primary cause?

Which of the following differentiates migraine from tension-type headaches?

How does cholesterol contribute to the body’s functions? 

A patient is diagnosed with Huntington’s disease, which is associated with an expansion of a CAG trinucleotide repeat. The patient’s father was diagnosed with Huntington’s at age 60, but the patient shows symptoms at age 45. What best explains this difference?

Which type of generalized epilepsy is characterized by brief lapses in awareness without motor symptoms?

What is the primary function of triglycerides in the body? 

Which of the following best describes the mechanism by which portions of two different homologous chromosomes can be exchanged during meiosis?