Meaning: 'Insatiably' means in a way that is impossible to satisfy, indicating that keas have an unending desire to explore and learn.

Wrong options:

• hungrily: While 'hungrily' suggests a strong desire, it typically relates to food and does not convey the same depth of curiosity as 'insatiably'.
• thirstily: Similar to 'hungrily', 'thirstily' implies a strong desire but is more commonly associated with needing water, making it contextually inappropriate for curiosity.
• unmanageably: This term suggests something difficult to control, which does not accurately describe the nature of curiosity and does not fit grammatically as it does not modify 'curious' correctly.

Correct answer: pick

Explanation: The verb 'pick' is appropriate here as it indicates the action of selecting or gathering tips, fitting grammatically in the present tense and contextually as it describes how keas learn from observing each other.

Meaning: 'Pick' means to choose or gather something, in this case, tips or information from their peers.

Wrong options:

• take: While 'take' could imply gathering, it lacks the specificity of 'pick' in the context of learning from observation.
• lift: This verb suggests raising something, which does not fit the context of acquiring knowledge or tips from watching others.
• pull: 'Pull' implies a physical action of drawing something towards oneself, which does not align with the context of learning or observing.

Correct answer: process

Explanation: The noun 'process' fits well as it refers to a series of actions or steps taken to achieve a particular end, aligning grammatically and contextually with the idea of keas' investigative behavior.

Meaning: 'Process' refers to a method or series of actions taken to achieve a result, in this case, the way keas investigate their environment.

Wrong options:

• procedure: 'Procedure' implies a specific method or set of instructions, which is too formal and does not capture the exploratory nature of keas' behavior.
• measure: This term refers to a standard unit or action taken to achieve something, which does not fit the context of curiosity and exploration.
• technique: While 'technique' suggests a skillful way of doing something, it is too narrow and does not encompass the broader investigative behavior of keas.

Correct answer: performed

Explanation: The verb 'performed' is suitable as it indicates that the birds executed the task, fitting grammatically in the past tense and contextually as it describes the action taken by the trained keas.

Meaning: 'Performed' means to carry out or execute a task, in this case, the keas executing the task of opening the box.

Wrong options:

• enacted: This term typically refers to putting something into action, often in a legal or formal context, which does not fit the informal setting of the keas' task.
• staged: 'Staged' implies a planned or rehearsed performance, which does not accurately describe the natural behavior of the keas in this context.
• presented: This verb suggests showing or displaying something, which does not accurately convey the action of completing a task.

Correct answer: Sure

Explanation: The adverb 'Sure' fits well as it expresses certainty, aligning grammatically and contextually with the statement that follows about the birds' success after watching the demonstration.

Meaning: 'Sure' means certain or confident, indicating that the statement is made with assurance based on the observed results.

Wrong options:

• Certain: While 'certain' conveys a similar meaning, it is an adjective and does not fit grammatically as an adverb in this context.
• True: This term implies factual correctness but does not convey the same level of confidence as 'sure' in this context.
• Fair: 'Fair' typically relates to justice or equality, which does not fit the context of expressing certainty about the birds' success.

Correct answer: rate

Explanation: The noun 'rate' is appropriate as it refers to a measure or level of success, fitting grammatically and contextually within the sentence discussing the success of the birds.

Meaning: 'Rate' refers to the level or frequency of something, in this case, the success rate of the birds who observed the demonstration.

Wrong options:

• proportion: This term refers to a part or share of a whole, which does not specifically convey the idea of success in the same way as 'rate'.
• percentage: While 'percentage' indicates a specific portion out of 100, it is too precise and does not fit the broader context of success level indicated by 'rate'.
• occurence: This noun refers to the frequency of something happening, which does not align with the context of measuring success.