Meaning: 'Livable' refers to a climate that is suitable for human habitation and well-being.

Wrong options:

• petition: 'Petition' is a noun that refers to a formal request, which does not describe a type of climate.
• action: 'Action' is a noun that refers to the process of doing something, which does not fit as a descriptor for climate.
• native: 'Native' is an adjective that describes something originating from a particular place, which does not apply to climate.
• tradition: 'Tradition' is a noun that refers to customs or beliefs passed down through generations, which does not relate to climate.

Correct answer: action

Explanation: The term 'action' is a noun that refers to the steps or measures taken to achieve a goal. It fits grammatically as it serves as the subject of the sentence, indicating what needs to be taken by governments and businesses.

Meaning: 'Action' refers to the steps or measures that need to be implemented to address an issue.

Wrong options:

• transition: 'Transition' is a noun that refers to the process of change, which does not fit as the immediate requirement for governments and businesses.
• livable: 'Livable' is an adjective that describes a climate, not an action that can be taken.
• petition: 'Petition' is a noun that refers to a formal request, which does not convey the necessary proactive measures required.
• native: 'Native' is an adjective that does not relate to the concept of taking measures or actions.
• tradition: 'Tradition' is a noun that refers to customs, which does not imply immediate action.

Correct answer: transition

Explanation: The word 'transition' is a noun that describes the process of changing from one state to another. It fits grammatically as it serves as the subject of the clause, indicating the necessary change towards a low-carbon world.

Meaning: 'Transition' refers to the process of moving from one state or condition to another, particularly in the context of adopting new practices.

Wrong options:

• action: 'Action' is a noun that refers to steps taken, which does not describe the process of change required for a low-carbon world.
• livable: 'Livable' is an adjective that describes a climate, not a process of change.
• petition: 'Petition' is a noun that refers to a formal request, which does not relate to the concept of change or transition.
• native: 'Native' is an adjective that does not pertain to the process of transitioning to a new state.
• tradition: 'Tradition' is a noun that refers to customs, which does not imply a process of change.