A child has an avulsed (knocked-out) tooth. In which medium should the nurse instruct the parents to place the tooth for transport to the dentist?

The correct answer is choice C: Concrete operations stage.

Choice A rationale:

The preoperational stage, which occurs roughly between ages 2 and 7, is characterized by egocentrism, animism, and a lack of conservation. Children in this stage struggle with understanding that quantities can remain the same even if their appearance changes. For instance, they might think that pouring water from a tall glass into a short, wide glass somehow changes the amount of water. This stage does not demonstrate the mental understanding required for the examples given in the question.

Choice B rationale:

The intuitive thought stage, which typically spans from ages 4 to 7, is marked by increased symbolic thinking but still lacks the capacity for logical and systematic reasoning. Children in this stage might be able to count and perform basic arithmetic, but they struggle with more complex operations and understanding the underlying principles of mathematical operations. This stage is not where the ability to understand the given math operations is firmly established.

Choice C rationale:

The concrete operations stage, which encompasses ages 7 to 11, is characterized by the development of logical and systematic thinking. Children in this stage are capable of understanding basic mathematical principles and operations, such as conservation of quantity and simple arithmetic. They can mentally manipulate numbers and understand that reversing an operation will yield the original quantity. Therefore, this stage is when the ability to understand that 1 + 3 = 4 and 4 - 3 = 1 occurs.

Choice D rationale:

The formal operations stage, typically beginning around age 11, is characterized by abstract and hypothetical thinking. This is when adolescents and adults can engage in complex reasoning and consider multiple possibilities and outcomes. The given math operations are not the focus of this stage; rather, it pertains to more advanced cognitive abilities like hypothetical problem-solving and deductive reasoning.

The correct answer is choice C.

Choice C rationale:

Placing the avulsed tooth in cold milk is the most suitable medium for transporting it to the dentist. Cold milk helps preserve the viability of the tooth's cells and tissues, which is crucial for successful reimplantation. The temperature and composition of cold milk provide a suitable environment to prevent cell damage.

Choice A rationale:

Placing the tooth in a dry, clean jar is not recommended. A dry environment can cause the tooth's cells to dry out and become nonviable, making reimplantation less successful.

Choice B rationale:

Warm salt water is not the optimal choice for transporting an avulsed tooth. Warm water can cause damage to the tooth's cells, and salt water may not provide the necessary conditions to maintain the tooth's viability.

Choice D rationale:

Placing the tooth in cold water might seem logical, but it is not as effective as cold milk. Cold water lacks the protective properties and nutrients that milk provides, potentially leading to a higher risk of cell damage in the avulsed tooth.