Given below are a few sentences with one blank in

Solution

In the context of the sentence, "tenacity" refers to the research team's determination and persistence, which ultimately led to a ground-breaking discovery. The word "tenacity" means the quality of being persistent and not giving up in the face of challenges. The other options are incorrect: b) Taciturnity: This word means reluctance to engage in conversation or being reserved in speech, which doesn't fit the context of the research team's dedication. c) Transcendence: While this word refers to surpassing something, it doesn't accurately convey the idea of the research team's persistence and dedication. d) Timidity: This word refers to a lack of self-confidence or hesitation, which doesn't match the determined attitude of the research team.