Meaning: 'Meeting' in this context means to fulfill or satisfy a requirement, specifically the consistent power demand of mobile phones.

Wrong options:

• engaging: Engaging implies involvement or participation, which does not fit the context of fulfilling a demand.
• keeping: Keeping suggests maintaining possession or control, which does not convey the idea of fulfilling a demand effectively.
• dealing: Dealing implies handling or managing a situation, which is not the precise action required in this context.

Correct answer: over

Explanation: The word 'over' is used here to indicate taking control or responsibility for something, which fits the context of the disposable battery stepping in when needed. It is a common collocation with 'take' in this context.

Meaning: 'Over' means to take control or responsibility for something, indicating that Instant Power will replace the rechargeable battery when it fails.

Wrong options:

• up: 'Up' does not convey the sense of taking control or responsibility, making it an inappropriate choice here.
• off: 'Off' suggests removal or disconnection, which does not fit the context of replacing a battery.
• on: 'On' implies activation or continuation, which does not align with the idea of taking over a function.

Correct answer: doing

Explanation: The word 'doing' fits grammatically as a gerund that indicates the action of eliminating or removing the need for something, which aligns with the context of not needing to carry a charger.

Meaning: 'Doing' in this context means to eliminate or remove the necessity of carrying a mains charger.

Wrong options:

• getting: 'Getting' implies obtaining or receiving, which does not convey the action of eliminating a need effectively.
• making: 'Making' suggests creating or causing, which does not fit the context of removing a necessity.
• putting: 'Putting' implies placing or positioning, which does not align with the idea of eliminating a requirement.

Correct answer: deteriorates

Explanation: The word 'deteriorates' fits grammatically as it describes the process of decline in quality or performance over time, which is appropriate in the context of batteries losing effectiveness as they age.

Meaning: 'Deteriorates' means to decline in quality or effectiveness, particularly relevant to how rechargeable batteries perform over time.

Wrong options:

• diminishes: 'Diminishes' suggests a reduction in size or importance, which is less specific than 'deteriorates' in the context of battery performance.
• declines: 'Declines' indicates a decrease but lacks the specific connotation of quality loss that 'deteriorates' provides.
• detracts: 'Detracts' implies a reduction in value or worth, which does not accurately describe the aging process of batteries.

Correct answer: concerned

Explanation: The word 'concerned' fits grammatically as it describes a state of worry or interest regarding the environment, which aligns with the context of discussing eco-friendliness.

Meaning: 'Concerned' means to be worried or interested about something, in this case, the environmental impact of products.

Wrong options:

• anxious: 'Anxious' implies a state of nervousness or unease, which is a stronger emotional response than simply being concerned.
• dubious: 'Dubious' suggests skepticism or doubt, which does not fit the context of expressing care for the environment.
• troubled: 'Troubled' indicates a deeper level of distress, which is not the intended sentiment in this context.