Chronic Lymphocytic Leukemia is characterized by gradual accumulation of small mature cells.

Correct Answer: B

Rationale: The correct answer is B because Chronic Lymphocytic Leukemia (CLL) is characterized by the gradual accumulation of small mature B cells in the blood and bone marrow. B cells are lymphocytes that play a key role in the immune system. Choice A (T cells) is incorrect because CLL primarily involves B cells, not T cells. Choice C (NK cells) is incorrect because CLL does not involve natural killer (NK) cells. Choice D (Mixed) is incorrect because CLL is characterized by the accumulation of a single type of cell, specifically mature B cells.

Correct Answer: D

Rationale: The correct answer is D because the transferrin receptor is responsible for transporting transferrin-bound iron into cells, particularly erythrocytes. This process allows for the delivery of iron to cells for various biological functions, such as hemoglobin synthesis. Choice A is incorrect as iron is typically absorbed into duodenal cells, not transported out. Choice B is incorrect as it does not align with the role of the transferrin receptor in importing iron. Choice C is incorrect as the transferrin-bound iron in the plasma is not directly handled by the transferrin receptor but rather serves as a carrier for iron transport.

Correct Answer: B

Rationale: The correct answer is B: Improper disposal of phlebotomy equipment. This is the most frequent cause of needle punctures because if needles are not disposed of properly, they can pose a risk of accidental needle sticks to healthcare workers. Patient movement during venipuncture (A) can lead to complications but is not the most frequent cause of needle punctures. Inattention during needle removal (C) and failure to attach needle firmly to the tube holder (D) are also important factors to consider, but improper disposal of needles presents a higher risk of needle punctures.

Correct Answer: B

Rationale: The correct answer is B: P. ovale. P. ovale can cause relapses of malaria due to the presence of dormant liver stages (hypnozoites) that can reactivate weeks to years after the initial infection. P. falciparum, P. malariae, and P. knowlesi do not have hypnozoites and therefore do not cause relapses. P. falciparum is known for its severe manifestations, P. malariae has a long incubation period but does not cause relapses, and P. knowlesi mainly infects monkeys and rarely causes human malaria.

Correct Answer: D

Rationale: The correct answer is D: delayed hypersensitivity. Hemolytic disease of the newborn caused by Rh incompatibility is a type II hypersensitivity reaction. Rh incompatibility occurs when an Rh-negative mother carries an Rh-positive fetus, leading to the mother producing antibodies against the Rh antigen. This immune response is delayed and involves sensitized T cells. This results in the destruction of Rh-positive red blood cells in the newborn. Choice A (atopic or anaphylactic) refers to type I hypersensitivity, which involves immediate IgE-mediated reactions like allergies. Choice B (cytotoxic) is a close contender, as it also involves antibodies targeting specific antigens on cell surfaces, but it typically involves antibody-dependent cell-mediated cytotoxicity rather than delayed responses. Choice C (immune complex) relates to type III hypersensitivity, where immune complexes deposit in tissues and activate complement, causing inflammation. However, this mechanism is not the primary process in hemolytic disease of the newborn caused by