One of the most common factors that compromise the vitamin D status of older adults, particularly those living in assisted living communities is _____.

Correct Answer: D

Rationale: The correct answer is 'D: lack of exposure to sunlight.' Older adults, especially those in assisted living communities, are at risk of vitamin D deficiency due to spending most of their time indoors, which reduces their exposure to sunlight. Sunlight is essential for the body to produce vitamin D. Choices A, B, and C are less likely to be major factors in compromising vitamin D status. While a decreased intake of fruits and vegetables and lack of physical activity can impact overall health, they are not as directly related to vitamin D status. Malabsorption due to atrophic gastritis may affect the absorption of certain nutrients, but vitamin D synthesis primarily depends on sunlight exposure.

Correct Answer: C

Rationale: The correct answer is C: vomiting. Infants breastfed by mothers who smoke are more likely to experience vomiting and gastrointestinal issues due to the transfer of nicotine and other harmful substances through breast milk. Choices A, B, and D are incorrect. Poor temperature regulation, vision impairment, and elevated blood pressure are not the primary outcomes closely associated with breastfeeding infants of mothers who smoke.

Correct Answer: C

Rationale: Handgrip strength is a reliable test to assess muscle function and detect muscle weakness due to wasting. It is often used to identify conditions like sarcopenia in clinical settings. Options A, B, and D are not suitable for evaluating muscle weakness. Food intake recall does not directly measure muscle function, skinfold thickness assesses body fat but not muscle strength, and red blood cell levels are unrelated to muscle wasting.

Correct Answer: B

Rationale: The correct answer is B: sulfur. Sulfur-containing amino acids like cysteine and methionine play a crucial role in forming disulfide bonds within proteins. These bonds are essential for the proper folding and structural stability of proteins. Phosphorus (choice A), selenium (choice C), and iron (choice D) do not directly contribute to shaping proteins through bond formation.

Correct Answer: A

Rationale: The correct answer is A: hemoglobin. Hemoglobin is the protein found in red blood cells that is responsible for carrying oxygen from the lungs to the rest of the body. Iron is a crucial component of hemoglobin, binding to oxygen and allowing for its transport. Choice B, transferrin, is involved in iron transport in the blood but not in oxygen transport. Choice C, myoglobin, is a protein found in muscle cells that stores oxygen for muscle use, not transportation in the bloodstream. Choice D, hepcidin, is a peptide hormone that regulates iron absorption in the intestines and iron distribution in the body, but it is not directly involved in oxygen transport.