Meaning: 'Deplete' means to use up or diminish resources, in this case, referring to energy reserves being reduced.

Wrong options:

• obsolete: Obsolete means no longer in use or outdated, which does not fit the context of energy reserves being affected.
• complete: Complete means to finish or finalize something, which does not relate to the reduction of energy reserves.
• delete: Delete means to remove or erase, which is not applicable in the context of energy reserves.

Correct answer: but

Explanation: The conjunction 'but' is used to contrast two ideas, indicating that despite working the same hours, the most productive employees took more breaks. This fits logically and contextually within the sentence structure.

Meaning: 'But' is used to introduce a contrast or exception, highlighting the difference between the productivity of the top 10 percent and the rest.

Wrong options:

• therefore: Therefore implies a conclusion or result, which does not fit the contrasting nature of the statement.
• although: Although introduces a dependent clause that does not fit the structure of the sentence as it requires a contrasting conjunction.
• so: So indicates a consequence, which does not align with the need for contrast in this context.

Correct answer: rest

Explanation: The verb 'rest' fits grammatically and contextually as it indicates the action needed for our eyes after prolonged focus. The sentence structure requires a verb that conveys the need for a break for the eyes.

Meaning: 'Rest' means to cease work or movement in order to relax or recover, particularly relevant for our eyes in this context.

Wrong options:

• function: Function refers to the purpose or role of something, which does not fit the context of needing a break for our eyes.
• arrest: Arrest means to stop or seize, which does not convey the intended meaning of allowing our eyes to recover.
• operate: Operate means to control or manage something, which is not relevant to the context of resting our eyes.

Correct answer: capacity

Explanation: The noun 'capacity' fits grammatically as it refers to the maximum amount that something can contain or the ability to do something. In this context, it relates to the limited ability to concentrate.

Meaning: 'Capacity' means the ability or power to do, experience, or understand something, particularly in relation to concentration.

Wrong options:

• audacity: Audacity means boldness or daring, which does not relate to the ability to concentrate.
• domesticity: Domesticity refers to home life or family affairs, which is irrelevant to the context of concentration.
• authenticity: Authenticity means the quality of being genuine or real, which does not pertain to the ability to concentrate.