A nursing instructor asks a nursing student to describe the route of transmission of tuberculosis. The instructor concludes that the student understands this information if the student states that tuberculosis is transmitted by:

Correct Answer: B

Rationale: The correct answer is B: The airborne route. Tuberculosis is primarily transmitted through the air when an infected person coughs or sneezes, releasing droplets containing the TB bacteria. These droplets can be inhaled by others, leading to the transmission of the disease. This mode of transmission is supported by scientific evidence and is well-documented in medical literature. Choice A (Hand to mouth) is incorrect because TB is not typically transmitted through direct contact with contaminated hands to mouth. Choice C (The fecal-oral route) is incorrect as TB is not transmitted through fecal-oral route but primarily through respiratory droplets. Choice D (Blood and body fluids) is incorrect as TB is not commonly transmitted through blood or body fluids, but rather through respiratory droplets in the air.

Correct Answer: A

Rationale: The correct answer is A: 78 percent. The rationale is based on the fact that nitrogen makes up approximately 78% of the Earth's atmosphere. This is a well-known scientific fact supported by various studies and measurements. Option B, C, and D are incorrect as they do not align with the established data on the composition of the Earth's atmosphere. Nitrogen is the most abundant gas in the atmosphere, followed by oxygen, which is around 21%. Therefore, option A is the correct choice based on scientific evidence and consensus.

Correct Answer: D

Rationale: Exhaling into a paper bag and rebreathing the exhaled air leads to an increase in carbon dioxide levels in the body. This increase stimulates the carotid bodies, which detect changes in blood chemistry, leading to an increase in breathing rate. This process does not directly alert the brain, as high carbon dioxide levels typically cause drowsiness rather than alertness. Therefore, the correct answer is D, as it correctly identifies the effects of rebreathing on both breathing rate and carotid body stimulation. Choice A is incorrect because rebreathing does not directly alert the brain. Choice B is incorrect as rebreathing actually decreases the need for increased breathing rate initially. Choice C alone is incorrect as it does not address the effect on breathing rate.

Correct Answer: B

Rationale: The correct answer is B: Pulmonary vein. Oxygenated blood from the lungs is carried to the heart by the pulmonary vein. After receiving oxygen in the lungs, blood returns to the heart via the pulmonary veins to be pumped to the rest of the body. The pulmonary artery (A) carries deoxygenated blood from the heart to the lungs. The coronary vein (C) drains deoxygenated blood from the heart muscle. Pre-cavals (D) is not a term used in the context of blood circulation.

Correct Answer: B

Rationale: The correct answer is B (0.3 and 32 mm Hg) because in inspired air, the partial pressure of carbon dioxide is low at around 0.3 mm Hg, whereas in expired air, the partial pressure of carbon dioxide is higher at around 32 mm Hg due to gas exchange in the lungs. Choice A (0.3 and 40 mm Hg) is incorrect because the partial pressure of carbon dioxide in inspired air is not typically as high as 40 mm Hg. Choice C (40 and 46 mm Hg) is incorrect because the values are reversed; the partial pressure of carbon dioxide is higher in expired air compared to inspired air. Choice D (40 and 0.3 mm Hg) is incorrect as the values are reversed, and the partial pressure of carbon dioxide in inspired air is not typically as high as 40 mm Hg.