The following text is adapted from a CEO’s retirement speech.

I do not regret dedicating my life to this company. I worked to my limit, as one should in any endeavor. There was no department I did not manage. But to have stayed as CEO for another decade would have been wrong because it would have been limiting. I had to make room for new leadership.

As used in the text, what does the word "limiting" most nearly mean?

To a traveler flying over the Arctic tundra in winter, the landscape may appear empty and lifeless; however, a closer inspection on the ground reveals a _______ ecosystem, alive with migrating caribou, arctic foxes, and resilient mosses.

In the days before the internet, librarians served as the gatekeepers of information, organizing books and guiding researchers. Their role was considered _______ to the functioning of a university, as they ensured that students could access the knowledge required for their studies.

Marine biologists suspect that the reason we rarely see giant squids is that they inhabit the "midnight zone" of the ocean, a depth where sunlight does not penetrate, rendering the creatures effectively _______ to observers on the surface.

The following text is adapted from a story about a failed merchant.

The merchant sat among his unsold goods, a man who had been unfortunate in business. He looked at the pile of silk that no one wanted, seeing it as a symbol of his poor judgment. "It is high quality silk," he whispered. "But the market has changed."

As used in the text, what does the word "unfortunate" most nearly mean?

Although many people believe that public speaking is a natural gift, communication experts argue that it is actually a skill that can be _______ through rehearsal and the study of rhetoric.

In his book on urban infrastructure, the engineer notes that while ancient Rome built aqueducts to move water, modern cities rely on pressurized pipe systems, a change which _______ the current layout of our subterranean utility grids.

The jazz pianist was known for his _______ style; he rarely played a song the same way twice, preferring instead to let the mood of the audience guide his fingers in the moment.

Traffic engineers use sensors to monitor the flow of cars on the highway. These sensors communicate with traffic lights, adjusting the timing of green lights based on the _______ of vehicles on the road to prevent congestion.

The following text is adapted from a story about an astronomer.

Dr. Sagan’s telescope was fixed on the distant star. He was thinking of the light that had traveled millions of years to reach him. He felt a sense of awe, as if the universe were waiting for him to understand it.

As used in the text, what does the word "fixed" most nearly mean?