Correct Answer: A

Rationale: The correct answer is A: Free radical theory. Vitamin C is thought to prevent aging by combatting free radicals, which are highly reactive molecules that can damage cells and contribute to aging. Vitamin C acts as an antioxidant, neutralizing free radicals and protecting cells from oxidative damage. Immunological theory (B) focuses on the role of the immune system in aging. Oxidative stress theory (C) is related to free radical theory but does not specifically address the role of vitamin C. Telomere theory (D) pertains to the shortening of telomeres, which are protective structures at the end of chromosomes, but is not directly related to the role of vitamin C in preventing aging.

Correct Answer: D

Rationale: The correct answer is D: Confusion or cognitive decline. In older adults, dehydration can manifest differently than in younger populations. Cognitive decline is a key sign of dehydration in older adults due to the brain being more sensitive to fluid loss. Dehydration can lead to confusion, disorientation, and impaired cognitive function in older individuals. Dark-colored urine (A) is a common sign of dehydration in all age groups. Increased thirst (B) is a general sign of dehydration but may not be as prominent in older adults due to decreased thirst sensation. Dry mouth and skin (C) are also common signs of dehydration but may not be as reliable indicators in older adults compared to cognitive changes.

Correct Answer: A

Rationale: Step 1: Gerontological nursing certification focuses on advanced knowledge and skills for caring for older adults. Step 2: This certification is not a requirement for all nurses in long-term care or limited to rehabilitation centers. Step 3: Nurses with various levels of education, not just a master's degree, can obtain gerontological certification. Therefore, option A is correct as it accurately states that gerontological nursing certification signifies advanced knowledge and skills specific to older adult care. Options B, C, and D are incorrect as they provide inaccurate information about the certification requirements and scope.

Correct Answer: D

Rationale: The correct answer is D: Circulatory problems related to age and a chronic illness. Severe edema, hair loss on the legs, and foot ulcerations are indicative of poor circulation, often seen in conditions like peripheral artery disease. Age and chronic illnesses can contribute to circulatory issues. A diet low in protein (choice A) would not directly cause these symptoms. Exposure to cold (choice B) would not explain the specific symptoms mentioned. Frequent falls (choice C) do not align with the symptoms provided.

Correct Answer: A

Rationale: The correct answer is A: Decreased manual dexterity and inability to hold a toothbrush. As people age, they may experience decreased hand strength and motor skills, making it difficult to hold and manipulate objects like a toothbrush. This can lead to a decline in oral hygiene practices. Malocclusion of teeth (B) does not directly impact the ability to brush teeth. Decrease in taste acuity (C) may affect appetite but not tooth brushing habits. Lack of dental insurance (D) is a financial barrier and may affect access to dental care, but it does not directly impact the physical ability to brush teeth.