Carbon dioxide and water combine to form

Correct Answer: C

Rationale: The correct answer is C: carbonic acid. When carbon dioxide and water combine, they form carbonic acid through a chemical reaction known as hydration. This process is essential for the transportation of carbon dioxide in the blood and plays a crucial role in maintaining the body's pH balance. Hydrochloric acid (A) is formed by the reaction of hydrogen chloride gas with water. Oxygen (B) is not a product of the reaction between carbon dioxide and water. Carbaminohemoglobin (D) is a compound formed by the binding of carbon dioxide to hemoglobin in red blood cells, not a direct product of the reaction between carbon dioxide and water.

Correct Answer: A

Rationale: The function of the conchae in the nasal cavity is to increase surface area. By increasing the surface area of the nasal cavity, conchae help to humidify, filter, and warm the air entering the respiratory system. This ensures optimal conditions for efficient gas exchange in the lungs. Choice B (exchange gases) is incorrect because gas exchange primarily occurs in the alveoli of the lungs, not in the nasal cavity. Choice C (maintain surface tension) is incorrect as surface tension is typically associated with liquid interfaces, not with the nasal cavity. Choice D (maintain air pressure) is also incorrect because the conchae do not play a direct role in maintaining air pressure within the nasal cavity.

Correct Answer: D

Rationale: The correct answer is D: cuneiform. The cuneiform cartilages are paired cartilages, not unpaired. The epiglottis, cricoid, and thyroid cartilages are unpaired cartilages of the larynx. The epiglottis functions in covering the larynx during swallowing, the cricoid provides support for the larynx, and the thyroid cartilage forms the "Adam's apple." The cuneiform cartilages, on the other hand, are small paired cartilages located within the aryepiglottic folds. They help maintain the shape and stiffness of these folds, assisting in vocal cord function.

Correct Answer: C

Rationale: The correct answer is C: Nasopharynx. The Eustachian tube connects the middle ear to the nasopharynx, allowing for pressure equalization. The oropharynx (A) and laryngopharynx (B) do not directly receive the Eustachian tube. Choice D is incorrect as the Eustachian tube does connect to a specific part of the pharynx.

Correct Answer: C

Rationale: The correct answer is C: When three consecutive sputum cultures are negative. This indicates successful treatment completion and eradication of the tuberculosis infection. A negative sputum culture confirms that the patient is no longer infectious and can safely discontinue the medication. Choice A is incorrect because a single negative sputum culture does not guarantee complete eradication of the infection. Choice B is incorrect as the standard treatment duration for tuberculosis is typically 6-9 months, but discontinuation should be based on sputum culture results. Choice D is incorrect as the TST can remain positive even after successful treatment, as it reflects exposure to the tuberculosis bacteria, not active infection status.