Correct Answer: D

Rationale: Prevident is indicated for all the situations listed in the choices. It is recommended for patients with a high risk of caries to reduce the risk of tooth decay. It is also used in dental procedures like crown and bridge work to strengthen enamel and prevent cavities. Furthermore, it is utilized for orthodontic decalcification to aid in remineralizing the tooth structure and prevent further damage. Therefore, the correct answer is 'All of the above.' While choices A, B, and C are individually correct, selecting 'All of the above' is the most appropriate as it encompasses all the possible indications for Prevident.

Correct Answer: B

Rationale: By the age of three, a child typically develops the motor skills needed to spear food with a fork. This is a critical milestone in self-feeding as it shows progress in fine motor coordination. Choice 'A' is incorrect because using utensils and a napkin properly is a skill that may take longer to develop and refine. Choice 'C' is not correct as measuring liquids requires a higher level of motor skills and understanding of quantities that a three-year-old child might not possess. Choice 'D' is also incorrect as the proper display of table manners is a complex skill that is typically learned over a longer period and involves social and cultural norms.

Correct Answer: C

Rationale: Saturated fats, such as those found in butter and lard, are typically solid at room temperature due to the lack of double bonds, which allows the fat molecules to pack closely together. Cholesterol (Choice A) is a steroid, not a fat, and while it's solid at room temperature, it doesn't fit the general category of 'lipid' in the context of this question. Phospholipids (Choice B) are a major component of all cell membranes and can be both solid and liquid at room temperature depending on their composition. Trans fats (Choice D) can also be solid or liquid at room temperature, but they are not typically referred to as 'lipids' in a general sense.

Correct Answer: B

Rationale: Lignin is the correct answer because it is a type of fiber that is not a carbohydrate and provides structure to plant cell walls. Gums (choice A), pectin (choice C), and cellulose (choice D) are all types of dietary fiber that are carbohydrates. Gums are a type of soluble fiber, pectin is found in fruits and is a soluble fiber, and cellulose is a type of insoluble fiber found in plant cell walls.

Correct Answer: A

Rationale: Carbohydrates are composed of carbon, hydrogen, and oxygen. These three elements combine to form the basic structure of carbohydrates. Oxygen is an essential element in carbohydrates, contributing to their chemical composition. Choice B (nitrogen) is incorrect as nitrogen is not a typical component of carbohydrates. Choice C (water) is incorrect as water is not an element but a compound composed of hydrogen and oxygen. Choice D (glucose) is incorrect as glucose is a specific type of sugar, not an element found in the composition of carbohydrates.