The muscle that separates the thoracic cavity from the abdominal cavity is

Correct Answer: B

Rationale: The diaphragm is the primary muscle dividing thoracic and abdominal cavities, aiding respiration. 'Diaphragm,' is correct, per anatomy (e.g., Moore). 'Intercostal,' assists breathing between ribs. 'Rectus abdominis,' is abdominal. 'Pectoralis major,' is chest. Diaphragm's septal role makes B the accurate answer.

Correct Answer: D

Rationale: Bacterial toxins harm hosts. 'Hemolysin,' is correct as the exception, an effect (lysing blood cells), not a toxin class, per microbiology (e.g., Tortora). 'Endotoxin,' is LPS from gram-negative bacteria. 'Exotoxin,' is secreted protein. 'Neurotoxin,' targets nerves. Hemolysin's specificity makes D the precise answer.

Correct Answer: C

Rationale: Deficiency diseases result from nutrient lack. 'Pneumonia,' is correct as the exception, infectious (bacterial/viral), per medicine (e.g., Harrison's). 'Scurvy,' (vitamin C), 'Rickets,' (vitamin D), and 'Beriberi,' (vitamin B1) are deficiencies. Pneumonia's infectious cause makes C the precise answer.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Musculoskeletal diseases affect bones and muscles. 'Tuberculosis,' is correct as the exception, infectious (lungs primarily), per orthopedics (e.g., Campbel's). 'Osteoarthritis,' 'Rheumatoid arthritis,' and 'Osteoporosis,' are musculoskeletal. Tuberculosis' unrelatedness makes D the accurate answer.