Correct Answer: B

Rationale: Swelling during acute inflammation is primarily caused by the accumulation of fluid exudate in the affected tissues. This fluid exudate contains proteins and cells that leak from blood vessels due to increased vascular permeability. Collagenase (Choice A) is an enzyme that breaks down collagen and is not directly responsible for swelling. Lymphocytic margination (Choice C) is the process where white blood cells line up along the blood vessel walls, which does not directly cause swelling. Anaerobic glycolysis (Choice D) is a metabolic process that occurs in the absence of oxygen and is not related to the mechanism of swelling in acute inflammation.

Correct Answer: B

Rationale: The correct answer is B: 'It decreases bone resorption and increases bone density.' Raloxifene, as a selective estrogen receptor modulator (SERM), works by reducing bone resorption (breakdown) and maintaining or increasing bone density. This mechanism helps in preventing further bone loss and can even increase bone mass. Choices A, C, and D are incorrect. Raloxifene does not stimulate the formation of new bone (choice A), increase calcium absorption in the intestines (choice C), or increase the excretion of calcium through the kidneys (choice D).

Correct Answer: B

Rationale: Hyperreflexia, or exaggerated reflexes, is a common sign of an upper motor neuron (UMN) lesion. An UMN lesion indicates damage to the central nervous system pathways that control movement. Hypotonia (choice A) refers to reduced muscle tone, which is more indicative of lower motor neuron lesions. Muscle atrophy (choice C) suggests long-standing denervation or disuse of muscles. Fasciculations (choice D) are involuntary muscle contractions that can be seen in lower motor neuron lesions, like in amyotrophic lateral sclerosis (ALS), rather than UMN lesions.

Correct Answer: A

Rationale: Lung cancer is the leading cause of cancer-related deaths in both men and women globally. It is strongly associated with smoking and exposure to environmental toxins. Breast cancer (choice B) primarily affects women, while colorectal cancer (choice C) and prostate cancer (choice D) are more gender-specific. Colorectal cancer is more common in both men and women but not the leading cause of cancer-related deaths.

Correct Answer: B

Rationale: Cytotoxic T cells are the key players in cell-mediated immunity as they directly attack cells displaying specific antigens. Lymphokine-producing cells (Choice A) are involved in cytokine production, while Helper T cells (Choice C) assist in activating other immune cells. Macrophages (Choice D) are phagocytic cells that engulf and digest pathogens, but they are not the primary cells responsible for directly attacking cells with specific antigens in cell-mediated immunity.