Meaning: 'Make' means to produce or create something, in this case, music by the manakin birds.

Wrong options:

• have: The verb 'have' implies possession and does not convey the action of producing music, making it contextually inappropriate here.
• get: The verb 'get' suggests obtaining or receiving, which does not align with the action of creating music, thus it is incorrect in this context.
• do: The verb 'do' is generally used for performing actions but does not specifically indicate the creation of music, making it unsuitable in this sentence.

Correct answer: long

Explanation: The word 'long' fits correctly as it indicates a duration of time, which is appropriate in the context of the sentence discussing past awareness of the bird's noise-making ability.

Meaning: 'Long' refers to an extended period of time, suggesting that ornithologists had been aware of the bird's abilities for a significant duration.

Wrong options:

• once: The word 'once' implies a single occurrence in the past, which does not fit the context of ongoing awareness over time.
• ever: The word 'ever' suggests a question of existence or occurrence, which does not convey the sense of duration needed here.
• still: The word 'still' implies continuity but does not indicate the length of time, making it less suitable in this context.

Correct answer: However

Explanation: The word 'However' serves as a discourse marker indicating a contrast to the previous statement, fitting well grammatically and contextually to introduce the new information about the student solving the puzzle.

Meaning: 'However' means 'in contrast' or 'nevertheless,' signaling a shift in the narrative to a positive outcome despite previous difficulties.

Wrong options:

• Accordingly: The word 'Accordingly' suggests a logical conclusion or result, which does not fit the contrasting context of the sentence.
• Moreover: The word 'Moreover' indicates an addition to the previous statement, which is not appropriate here as it does not convey contrast.
• Whereas: The word 'Whereas' is used to compare two different situations, but it does not effectively introduce the new information as 'However' does.

Correct answer: at

Explanation: The preposition 'at' is the correct choice as it indicates a specific point in time or rate, fitting grammatically and contextually with the phrase 'a speed of a thousand frames per second.'

Meaning: 'At' is used to specify a particular rate or level, in this case, the speed of the camera's recording.

Wrong options:

• for: The preposition 'for' indicates duration or purpose, which does not fit the context of specifying a speed.
• by: The preposition 'by' suggests a method or means, which is not appropriate when discussing a specific speed.
• in: The preposition 'in' typically indicates a location or time frame, but does not correctly convey the idea of speed in this context.

Correct answer: as

Explanation: The word 'as' is the correct choice because it indicates a comparison between the actions of the manakin and guitarists, fitting grammatically and contextually in the sentence.

Meaning: 'As' is used to indicate similarity or manner, in this case, comparing how the bird uses its feather to how guitarists use a plectrum.

Wrong options:

• than: The word 'than' is used for comparisons of inequality, which does not fit the context of similarity required here.
• like: The word 'like' is used for informal comparisons but does not fit the grammatical structure needed in this sentence.
• so: The word 'so' indicates a result or consequence, which does not appropriately convey the comparative relationship intended in this context.