Meaning: An 'ecosystem' is a community of living organisms interacting with their environment.

Wrong options:

• arid: The word 'arid' is an adjective that describes a dry environment, which contradicts the context of urban green spaces that support life.
• responsibility: 'Responsibility' is a noun that refers to a duty or obligation, which does not fit as it does not describe a biological or environmental concept.
• comfortable: 'Comfortable' is an adjective that describes a state of physical ease, which does not relate to the ecological context of the sentence.
• flora: 'Flora' refers to the plant life in a particular region, but it does not encompass the broader interactions within an ecosystem, making it too narrow for this context.
• liveable: 'Liveable' is an adjective that describes the quality of being suitable for living, which does not fit as it does not pertain to the ecological interactions being discussed.

Correct answer: liveable

Explanation: The word 'liveable' is an adjective that describes the quality of a place being suitable for living. In this context, it fits grammatically and contextually as it describes how green spaces enhance the quality of urban life, making cities more pleasant to inhabit.

Meaning: 'Liveable' means suitable for living in, providing comfort and quality of life.

Wrong options:

• arid: 'Arid' is an adjective that describes a dry and barren environment, which is the opposite of what green spaces provide.
• responsibility: 'Responsibility' is a noun that does not fit in this context as it does not describe a quality of living conditions.
• comfortable: 'Comfortable' is an adjective that describes physical ease but does not specifically address the suitability of a place for living.
• ecological: 'Ecological' is an adjective that relates to the relationships between living organisms and their environment, which does not directly describe the quality of life in urban settings.
• flora: 'Flora' refers to plant life and does not pertain to the overall livability of an area.

Correct answer: ecological

Explanation: The term 'ecological' is an adjective that pertains to the relationships between living organisms and their environment. It fits grammatically and contextually as it describes the type of development that is sustainable and beneficial for both the environment and urban life.

Meaning: 'Ecological' relates to the interactions and relationships within ecosystems, emphasizing sustainability.

Wrong options:

• arid: 'Arid' is an adjective that describes a dry environment, which is contrary to the concept of sustainable development in urban settings.
• responsibility: 'Responsibility' is a noun that does not fit as it does not describe a type of development.
• comfortable: 'Comfortable' is an adjective that describes physical ease, which does not relate to the concept of development in an ecological context.
• ecosystem: 'Ecosystem' is a noun that refers to a community of organisms, but it does not describe the type of development being discussed.
• flora: 'Flora' refers to plant life and does not pertain to the concept of development.

Correct answer: responsibility

Explanation: The word 'responsibility' is a noun that refers to the duty or obligation individuals have towards their environment. It fits grammatically and contextually as it describes the sense of ownership and accountability that communities develop when engaged in the maintenance of green spaces.

Meaning: 'Responsibility' means having a duty to deal with something or having control over someone.

Wrong options:

• arid: 'Arid' is an adjective that describes a dry environment, which does not relate to the concept of community engagement or ownership.
• comfortable: 'Comfortable' is an adjective that describes a state of physical ease, which does not fit the context of community involvement and duty.
• ecological: 'Ecological' is an adjective that relates to ecosystems but does not convey the sense of duty or ownership required in this context.
• ecosystem: 'Ecosystem' is a noun that refers to a biological community, which does not fit as it does not describe a sense of duty or responsibility.
• flora: 'Flora' refers to plant life and does not pertain to the concept of community responsibility.