Meaning: 'Cumbersome' means difficult to handle or manage due to size or complexity.

Wrong options:

• labyrinth: The term 'labyrinth' refers to a complicated network of paths or a maze, which does not fit grammatically as it is a noun and does not describe the nomenclature directly.
• subtle: 'Subtle' is an adjective that means delicate or understated, which does not convey the idea of being difficult or unwieldy, making it contextually inappropriate here.
• reciprocate: 'Reciprocate' is a verb meaning to respond to an action by making a corresponding one, which does not fit the context of describing the nomenclature.
• system: 'System' is a noun that refers to a set of connected things or parts, but it does not describe the nature of the nomenclature and is not an appropriate adjective here.
• revert: 'Revert' is a verb meaning to return to a previous state, which does not describe the nomenclature itself and is not suitable as an adjective.

Correct answer: revert

Explanation: The verb 'revert' means to return to a previous state or condition. In this context, it indicates that chemists preferred to go back to using older trivial names instead of the new nomenclature. This fits grammatically as it follows 'to' and aligns with the context of preference expressed in the sentence.

Meaning: 'Revert' means to go back to a previous state or condition.

Wrong options:

• system: 'System' is a noun that does not fit grammatically after 'to' as it does not indicate an action of returning.
• cumbersome: 'Cumbersome' is an adjective and cannot function as a verb in this context, making it grammatically incorrect here.
• labyrinth: 'Labyrinth' is a noun that does not convey an action and is not suitable in this context.
• subtle: 'Subtle' is an adjective that does not indicate an action and is not appropriate here.
• reciprocate: 'Reciprocate' is a verb that means to respond in kind, which does not fit the context of returning to a previous naming convention.

Correct answer: system

Explanation: The word 'system' is a noun that refers to a set of principles or procedures according to which something is done. In this context, it contrasts with 'tradition' and indicates that some scientists prioritize traditional naming over systematic approaches. This fits grammatically as a noun and logically completes the thought of the sentence.

Meaning: 'System' refers to an organized method or structure, in this case, the systematic nomenclature.

Wrong options:

• cumbersome: 'Cumbersome' is an adjective and does not fit grammatically as a noun in this context.
• revert: 'Revert' is a verb that does not fit as it does not serve as a noun in this context.
• labyrinth: 'Labyrinth' is a noun that refers to a complex structure, which does not logically fit in the context of comparing it to tradition.
• subtle: 'Subtle' is an adjective that does not function as a noun and does not fit the context of the sentence.
• tradition: 'Tradition' is a noun that refers to customs or beliefs passed down, but it does not fit the contrast being made with 'system'.