Which word means to place under observation?

In this context, the word "aegis" means a responsibility or authority for providing immunizations to the indigent population.

It implies that the public health department has the duty or obligation to undertake this task. The options "respectability," "relationship," and "ramifications" do not accurately reflect the meaning of "aegis" as it is used in this sentence.

In this context, the word "discrete" means separate or distinct.

It suggests that the person had three distinct symptoms that were not overlapping or connected. The doctor created an elaborate plan of care based on each individual symptom. The word "discrete" emphasizes the separateness and individuality of the symptoms.

Hold fast or stick.

In this context, "adhere" means to stick or hold fast to something. The sentence suggests that it was important for the mailing label to securely stick to the package. By adhering to the package, the label ensures that the box doesn't become lost during transit.

Refrain.

In this context, "abstain" means to voluntarily choose not to do something or to refrain from a particular action. The sentence suggests that people who have an allergy to wheat should avoid or refrain from eating pasta. The word "abstain" implies a conscious decision to abstain or avoid something due to a specific reason or condition. Therefore, option A, "Refrain," is the correct answer.