Meaning: 'Making' means to create or cause something to happen, in this case, improving the energy efficiency of buildings.

Wrong options:

• building: 'Building' refers to the act of constructing something new, which does not fit the context of improving existing structures.
• taking: 'Taking' implies receiving or acquiring, which does not convey the intended action of enhancing buildings.
• hiring: 'Hiring' means to employ someone for a job, which is unrelated to the context of modifying buildings for energy efficiency.

Correct answer: meeting

Explanation: 'Meeting' is the appropriate choice as it indicates the act of fulfilling or satisfying today's environmental standards, which is the intended meaning in the context of the sentence.

Meaning: 'Meeting' means to satisfy or comply with a requirement or standard, in this case, environmental standards.

Wrong options:

• searching: 'Searching' implies looking for something, which does not fit the context of fulfilling standards.
• starting: 'Starting' suggests beginning something, which does not align with the idea of complying with established standards.
• investing: 'Investing' refers to allocating resources for future benefits, which does not convey the action of fulfilling standards.

Correct answer: without

Explanation: 'Without' is the correct choice as it indicates the condition of achieving something in the absence of compromising historical integrity, fitting grammatically and contextually into the sentence.

Meaning: 'Without' means in the absence of or not having something, here referring to not compromising integrity.

Wrong options:

• by: 'By' indicates the means or method of doing something, which does not fit the context of avoiding compromise.
• due to: 'Due to' suggests a cause or reason, which does not align with the intended meaning of avoiding compromise.
• under: 'Under' implies a condition or state, which does not convey the intended meaning of not compromising integrity.

Correct answer: blend

Explanation: 'Blend' is the correct answer as it indicates the action of combining the new with the old, which is the focus of urban planning in the context of the sentence.

Meaning: 'Blend' means to mix or combine different elements together, in this case, new developments with historical architecture.

Wrong options:

• commoditize: 'Commoditize' means to turn something into a commodity, which does not fit the context of integrating new and old.
• orient: 'Orient' refers to positioning or aligning something, which does not convey the idea of combining elements.
• network: 'Network' implies creating a system of connections, which is unrelated to the idea of blending new and old architectural styles.