In the following question, select the one word that best substitutes the given phrase: “Not allowing fluid to pass through.”

Introduction / Context:
This vocabulary item checks your ability to choose a single word that replaces the descriptive phrase “not allowing fluid to pass through.” This concept is common in physics, engineering and everyday situations where we describe materials as waterproof or resistant to liquids. The correct term in the options uses a root that means “not able to be passed through or affected by something.”

Given Data / Assumptions:

• The phrase defines a property of a material that blocks fluid from passing through it.
• Impervious means not allowing fluid to pass through or not being affected by something.
• Envious means feeling or showing envy, which is an emotion, not a physical property.
• Conscious refers to being aware of and responding to one's surroundings.
• Nauseous means feeling sick, especially as if about to vomit.
• The answer should be an adjective describing resistance to fluid flow.

Concept / Approach:
In one word substitution questions, pay attention to the scientific or physical dimension of the phrase. Here, the phrase is clearly about permeability to fluids. The root pervious suggests allowing passage, while the prefix im indicates negation. Impervious thus literally means not pervious. The other adjectives refer to emotions or mental states and have nothing to do with material properties. Eliminating those options allows you to focus on the one that correctly encodes the physical meaning.

Step-by-Step Solution:
Step 1: Interpret the phrase as describing something similar to waterproof or impermeable. Step 2: Look at Impervious. It is defined as not permitting the passage of fluid and can also mean not being affected by something. This aligns exactly with the given phrase. Step 3: Evaluate Envious. It describes a person who feels jealousy or envy; it does not relate to fluid movement. Step 4: Consider Conscious. This adjective describes awareness, which is a mental condition, not a material property. Step 5: Consider Nauseous. It describes feeling sick to the stomach, also unrelated to permeability. Step 6: Therefore, Impervious is the only word that correctly matches the phrase.

Verification / Alternative check:
Try using the word in a sentence similar to the phrase: “This jacket is impervious to water” means water cannot penetrate it, which matches “not allowing fluid to pass through.” Sentences such as “this jacket is envious” or “this wall is nauseous” clearly make no sense. You can also recall that in science, impermeable or impervious layers are those that block fluid flow, confirming that Impervious is the precise match.

Why Other Options Are Wrong:
Envious is an emotional description, Conscious is about awareness and Nauseous relates to physical discomfort or sickness. None of them expresses any idea about permeability or resistance to fluid. Using any of these words to replace the phrase in technical or everyday descriptions of materials would distort the meaning and sound incorrect.

Common Pitfalls:
Students sometimes confuse Impervious with Impervious to criticism in a figurative sense and forget that its basic meaning is physical. Remember that many adjectives used metaphorically retain their original literal meanings. Another pitfall is focusing only on the negative prefix im and treating any adjective with that prefix as a potential answer. Always cross check that the core of the word, here pervious, relates to passage or permeability.

Final Answer:
The correct one word substitute for “not allowing fluid to pass through” is Impervious, so the correct answer is option Impervious.