Correct Answer: B

Rationale: A balanced chemical equation must have the same number of atoms of each element on both sides of the equation. In option B, 2H2 + O2 → 2H2O, the equation is balanced as there are 2 hydrogen atoms and 2 oxygen atoms on both the reactant and product sides after balancing, satisfying the law of conservation of mass. Option A is unbalanced as there are 2 oxygen atoms on the reactant side but only 1 oxygen atom on the product side. Option C is unbalanced with 3 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side. Option D is unbalanced with 1 oxygen atom on the reactant side and 2 oxygen atoms on the product side.

Correct Answer: B

Rationale: The correct answer is B, Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart's right ventricle to the lungs for oxygenation. This blood then undergoes the gas exchange process in the lungs, where carbon dioxide is removed, and oxygen is absorbed. The pulmonary vein, identified in choice A, carries oxygenated blood from the lungs back to the heart, which is the opposite direction of the blood flow specified in the question. Choice C, Aorta, is responsible for carrying oxygen-rich blood from the heart's left ventricle to the rest of the body, not to the lungs. Choice D, Superior vena cava, returns deoxygenated blood from the upper body to the heart's right atrium, but it does not transport blood specifically to the lungs as requested in the question.

Correct Answer: B

Rationale: The correct answer is B: Bacteria. Dysentery is typically caused by bacterial infections, such as Shigella, Campylobacter, or Escherichia coli. While parasites and protozoa can also cause similar symptoms, bacterial infections are the most common causes of dysentery. Choice A (Helminth) is incorrect as helminths are parasitic worms that typically cause different types of infections. Choice C (Protozoan) is incorrect as some protozoa like Entamoeba histolytica can cause dysentery, but bacterial infections are more common. Choice D (Fungus) is incorrect as fungal infections do not typically cause dysentery.

Correct Answer: C

Rationale: Total lung capacity is the correct term for the maximum volume of air that the lungs can hold after a full forced inhalation. It represents the sum of all lung volumes, including tidal volume, inspiratory reserve volume, and expiratory reserve volume. Inspiratory capacity refers to the maximum volume of air inspired from the end-expiratory level. Tidal volume is the volume of air inspired or expired during normal breathing. Vital capacity is the maximum volume of air that can be exhaled after a maximum inhalation, not the total volume the lungs can hold.

Correct Answer: A

Rationale: The correct arrangement of the small intestine segments, from the stomach to the large intestine, is Duodenum, Jejunum, and Ileum. The small intestine begins with the duodenum, then continues to the jejunum, and finally, it ends with the ileum before connecting to the large intestine. Option A, 'Duodenum, Jejunum, Ileum,' is the correct sequence. Choices B and C have the segments in incorrect order, not following the anatomical arrangement of the small intestine. Therefore, they are incorrect. Option D, 'None of the above,' is also incorrect as the correct sequence is provided in option A.