Select the meaning of the underlined word in this sentence.

The etiology of the flu epidemic of 1918 remains unknown to this day

The sentence suggests that the plumber used a tube to open up the blocked pipe, indicating that the tube needs to be able to navigate through the pipe's twists and turns. In this context, a flexible tube would be the appropriate choice, as it can bend and maneuver within the pipe. The options "rigid," "solid," and "perforated" do not convey the same idea of flexibility and adaptability as "flexible" does in this context.

The sentence suggests that the new mother prefers to use cloth diapers instead of disposables. The word "cloth" is the appropriate choice, as it specifically refers to a material that can be used for making diapers. The options "close," "clothes," and "clothing" do not fit the context of the sentence and do not convey the intended meaning.

Two-sided.

In medical terminology, "bilateral" refers to something that affects or is present on both sides. In the context of the sentence, it indicates that the weakness observed in the patient's ambulation is affecting both sides or both legs. The word "bilateral" is used to describe a condition or characteristic that is symmetrical or occurring on both sides of the body. Therefore, option A, "Two-sided," is the correct answer.

Pondering.

In the given sentence, "exasperatingly" is used as an adverb to describe how the person concluded their contemplation of their financial circumstances. "Exasperatingly" means in an irritated or frustrated manner. It suggests that the person reached their conclusion while feeling exasperation or annoyance with their present financial situation.

Option D, "Pondering," is the correct answer as it aligns with the act of contemplating or thinking deeply about something, which is the main action described in the sentence.