Meaning: 'Experiments' are scientific procedures undertaken to make a discovery, test a hypothesis, or demonstrate a known fact.

Wrong options:

• experiences: 'Experiences' refers to events or occurrences that one lives through, which does not fit the scientific context of conducting tests.
• contests: 'Contests' imply competitions, which are unrelated to the scientific investigation of taste.
• attempts: 'Attempts' suggests efforts made to achieve something but lacks the specificity of a scientific method, making it less suitable in this context.

Correct answer: popular

Explanation: The word 'popular' is an adjective that describes something widely liked or appreciated, which fits the context of MSG becoming well-known and favored around the world. It aligns with the grammatical structure of the sentence, indicating the widespread acceptance of MSG.

Meaning: 'Popular' means well-liked or enjoyed by many people, indicating that MSG became a common seasoning used globally.

Wrong options:

• spread: 'Spread' implies distribution but does not convey the idea of being well-liked or accepted, making it contextually inappropriate here.
• exported: 'Exported' refers to sending goods to another country, which does not capture the essence of MSG's acceptance and popularity.
• exclusive: 'Exclusive' suggests something limited to a particular group, which contradicts the idea of MSG being widely accepted.

Correct answer: tongue

Explanation: The word 'tongue' is a noun that refers to the organ in the mouth responsible for taste, making it the correct choice in this context. It fits grammatically and contextually, as the sentence discusses taste receptors located on this specific organ.

Meaning: 'Tongue' is the muscular organ in the mouth that is essential for tasting food and speaking.

Wrong options:

• fingers: 'Fingers' are not involved in taste perception, making this option irrelevant in the context of taste receptors.
• mouth: While the mouth is related to taste, it is too broad and does not specifically refer to the organ responsible for taste sensation.
• jaws: 'Jaws' refer to the bony structures that hold the teeth, which do not play a role in taste perception, thus making it an incorrect choice.

Correct answer: predominate

Explanation: The word 'predominate' is a verb that means to be the strongest or main element, fitting the context of the prevailing belief in the scientific community regarding umami. It aligns grammatically and contextually, indicating that this belief was the dominant view before the breakthrough.

Meaning: 'Predominate' means to be the most common or influential, suggesting that the belief about umami was the prevailing thought among scientists.

Wrong options:

• insignificant: 'Insignificant' means not important or trivial, which contradicts the context of discussing a widely held belief in the scientific community.
• important: 'Important' is a general term that does not convey the idea of being the main or dominant belief, making it less precise in this context.
• erroneous: 'Erroneous' means incorrect or mistaken, which does not fit the context of describing the prevailing wisdom, as it implies a judgment rather than a description of dominance.