Meaning: 'Responsible' means being the cause of something, in this case, climate change.

Wrong options:

• halt: 'Halt' is a verb meaning to stop something, which does not fit as it does not describe the pollutant.
• available: 'Available' is an adjective that means something is present or ready for use, which does not relate to the role of the pollutant.
• capture: 'Capture' is a verb that means to take something into possession, which does not describe the pollutant's role in climate change.
• offset: 'Offset' is a verb that means to counteract or compensate for something, which does not describe the pollutant itself.
• deliver: 'Deliver' is a verb meaning to bring or hand over something, which does not fit the context of describing a pollutant.

Correct answer: halt

Explanation: The term 'halt' is a verb that means to stop or bring to a standstill. It fits grammatically as it follows the auxiliary verb 'are' and aligns with the context of efforts to stop the production of greenhouse gases.

Meaning: 'Halt' means to stop something from continuing.

Wrong options:

• responsible: 'Responsible' is an adjective and does not fit as a verb in this context.
• available: 'Available' is an adjective that does not convey an action and is not suitable here.
• capture: 'Capture' is a verb that means to take possession of something, which does not fit the context of stopping production.
• offset: 'Offset' is a verb that means to counterbalance, which does not fit the context of stopping production.
• deliver: 'Deliver' is a verb that means to bring or hand over something, which does not relate to stopping production.

Correct answer: capture

Explanation: The word 'capture' is a verb that means to take something into possession. It fits grammatically as it follows 'want to' and contextually aligns with the goal of taking greenhouse gases from the air.

Meaning: 'Capture' means to take something into possession, in this case, greenhouse gases from the air.

Wrong options:

• responsible: 'Responsible' is an adjective and does not fit as a verb in this context.
• halt: 'Halt' is a verb meaning to stop, which does not fit the context of taking something from the air.
• available: 'Available' is an adjective that does not convey an action and is not suitable here.
• offset: 'Offset' is a verb that means to counterbalance, which does not fit the context of taking gases from the air.
• deliver: 'Deliver' is a verb that means to bring or hand over something, which does not relate to capturing gases.