Meaning: 'Laid' means to put something down in a specific place or to establish something, in this case, the foundations of social sciences.

Wrong options:

• pulled: 'Pulled' means to draw something towards oneself, which does not fit the context of establishing foundational concepts.
• allowed: 'Allowed' means to permit something, which does not convey the action of establishing or setting forth ideas.
• fabricated: 'Fabricated' means to invent or create something, often with a connotation of deceit, which is not appropriate in the context of laying out foundational concepts.

Correct answer: introduced

Explanation: The word 'introduced' is appropriate as it indicates that Khaldun brought forth new concepts into the discourse of social sciences. This aligns with the context of presenting new ideas, making it grammatically and contextually correct.

Meaning: 'Introduced' means to bring something into use or to present something for the first time, in this case, new concepts like 'Asabiyyah.'

Wrong options:

• controverted: 'Controverted' means to dispute or argue against something, which does not fit the context of presenting new ideas.
• assisted: 'Assisted' means to help or aid, which does not convey the action of bringing forth new concepts.
• digested: 'Digested' means to process information, which does not fit the context of introducing new ideas.

Correct answer: ahead

Explanation: The word 'ahead' fits well as it indicates that Khaldun's ideas were progressive and forward-thinking, which is consistent with the context of being influential beyond his time. It aligns grammatically and contextually with the sentence.

Meaning: 'Ahead' means in advance of a particular time or situation, suggesting that Khaldun's ideas were innovative and forward-looking.

Wrong options:

• behind: 'Behind' suggests being late or not keeping up, which contradicts the notion of being influential and progressive.
• toward: 'Toward' indicates direction but does not convey the idea of being ahead in terms of time or influence.
• forward: 'Forward' implies a direction but lacks the temporal context that 'ahead' provides in this sentence.

Correct answer: Despite

Explanation: The word 'Despite' is suitable as it introduces a contrast between the breadth of Khaldun's work and his recognition. It fits grammatically and contextually, indicating that even with significant contributions, he remains lesser-known.

Meaning: 'Despite' means in spite of or regardless of, indicating a contrast between two ideas.

Wrong options:

• Regardless: 'Regardless' is similar but does not fit as smoothly in the sentence structure compared to 'Despite.'
• Since: 'Since' indicates a time relationship, which does not convey the contrast needed in this context.
• Even though: 'Even though' is a conjunction that introduces a dependent clause, making it less suitable for this structure.

Correct answer: mainstream

Explanation: The word 'mainstream' is appropriate as it refers to the dominant trends or ideas in society. It fits grammatically and contextually, indicating that Khaldun is not widely recognized in the common historical narrative.

Meaning: 'Mainstream' refers to the prevailing or dominant ideas and practices in a particular field or society.

Wrong options:

• rigorous: 'Rigorous' means strict or demanding, which does not fit the context of recognition in historical narratives.
• crucial: 'Crucial' means extremely important, but it does not convey the idea of being widely accepted or recognized.
• sufficient: 'Sufficient' means adequate or enough, which does not relate to the concept of being widely known or recognized.