Correct Answer: B

Rationale: The correct answer is B: Presbycusis. Presbycusis refers to age-related hearing loss, commonly affecting higher frequencies. As people age, changes in the inner ear structures can lead to hearing loss. Otoplasty (A) is a surgical procedure to correct ear deformities, not related to aging. Otalgia (C) refers to ear pain, not specifically related to aging. Tinnitus (D) is the perception of ringing or buzzing in the ears, which can occur at any age and is not exclusive to age-related hearing loss.

Correct Answer: C

Rationale: Rationale for Answer C: Antibodies are produced by the B-cells. B-cells are a type of lymphocyte that differentiate into plasma cells, which are responsible for producing antibodies in response to antigens. This process is a key component of the humoral immune response. Therefore, the statement that antibodies are produced by the B-cells is true. Summary of Incorrect Choices: A: Antibody-mediated defense occurs through the B-cell system, not the T-cell system. T-cells are involved in cell-mediated immunity. B: Cellular immunity is mediated by T-cells, not antibodies produced by B-cells. D: Lymphocytes increasing with an allergic response is not directly related to the production of antibodies by B-cells. Allergic responses involve a different mechanism.

Correct Answer: C

Rationale: Step-by-step rationale for choice C: Angioedema differs from urticaria as it involves deeper swelling in the dermis and subcutaneous tissue, leading to a more profound and firm texture. This contrasts with urticaria, which presents as superficial, raised wheals on the skin. Therefore, option C is correct. Summary of other choices: A: Angioedema is not typically associated with intense itching, so it is not more pruritic than urticaria. B: Angioedema does not have small, fluid-filled vesicles like in allergic contact dermatitis. D: Angioedema tends to last longer than urticaria, making this statement incorrect.

Correct Answer: C

Rationale: The correct answer is C: Normal saline solution. Phenytoin is incompatible with dextrose solutions, so options A and D are incorrect. Lactated Ringer's solution contains calcium, which can interact with phenytoin, leading to precipitation. Therefore, option B is also incorrect. Normal saline is the most compatible diluent for phenytoin, maintaining the drug's stability and effectiveness. It is essential to use the appropriate diluent to prevent adverse reactions or drug interactions.

Correct Answer: D

Rationale: The correct answer is D: 60 seconds. This is because the area must be cleaned for at least 60 seconds to effectively disinfect the skin and reduce the risk of infection during venipuncture. Cleaning for shorter durations (5, 10, or 30 seconds) may not be sufficient to achieve proper disinfection. Thoroughly cleaning the area for a full minute ensures that the alcohol has enough time to kill bacteria and pathogens on the skin, making it safer for the venipuncture procedure. Shorter cleaning times may leave pathogens behind, increasing the risk of contamination and infection.