Correct Answer: A

Rationale: Immunological memory is primarily maintained by the clonal expansion of memory B cells. Memory B cells are a type of long-lived immune cell that originates from previously activated B cells during an immune response to a pathogen. When the immune system encounters the same pathogen again, memory B cells can quickly recognize and respond to it by undergoing rapid clonal expansion and differentiation into plasma cells that produce specific antibodies. This quick and robust response leads to the more efficient elimination of the pathogen during secondary exposure, resulting in the faster and stronger immune response characteristic of immunological memory.

Correct Answer: A

Rationale: Calcium carbonate should be taken with meals because it requires the presence of stomach acid to be properly absorbed. Taking it with meals helps ensure optimal absorption and effectiveness as a phosphate binder in patients with chronic kidney disease. Administering calcium carbonate on an empty stomach may lead to gastrointestinal side effects such as upset stomach, bloating, and constipation. Taking it with a full glass of water is also recommended to help prevent potential gastrointestinal issues and to ensure proper hydration. Crushing tablets before administration is not advised unless specifically instructed by a healthcare provider, as it can alter the drug's release and absorption properties.

Correct Answer: A

Rationale: When a baby is placed on phototherapy, especially for treating jaundice, it is crucial for the nurses to put sunglasses on the newborn to protect their eyes. Phototherapy involves exposing the baby's skin to certain types of light to help break down the bilirubin causing the jaundice. However, this light can be harmful to the baby's sensitive eyes, potentially leading to eye damage or other eye-related issues if not protected adequately. Therefore, placing sunglasses on the newborn is a necessary precaution to ensure the safety and well-being of the baby's eyes during the treatment.

Correct Answer: A

Rationale: For a patient diagnosed with a hemorrhagic stroke, the caregiver should ensure that the bed is positioned in a High-Fowler's position. This position involves elevating the head of the bed between 60 to 90 degrees. Elevating the head of the bed helps to reduce intracranial pressure and promote optimal cerebral perfusion. It also assists in maintaining proper ventilation and oxygenation, which are essential for the patient's recovery. It is important to avoid positioning the patient flat or in a prone position as these may exacerbate the condition and lead to further complications.

Correct Answer: C

Rationale: A living will is a legal document that outlines a person's preferences and wishes regarding medical treatment, including resuscitation, in the event they become unable to communicate or make decisions. In this scenario, the client being admitted to the oncology unit wants to convey his wishes regarding resuscitation in case of cardiopulmonary arrest. A living will helps ensure that these wishes are known and respected by healthcare providers and loved ones. While a will addresses how a person's assets should be distributed after death and a health care power of attorney designates someone to make medical decisions on the person's behalf, a living will specifically focuses on healthcare preferences and treatment decisions. A proxy directive is similar to a health care power of attorney, designating someone to make healthcare decisions for the person if they are unable to do so themselves.