Meaning: 'Perceive' means to become aware of or to interpret something through the senses, in this case, how animals sense or experience time.

Wrong options:

• deceive: 'Deceive' means to mislead or trick someone, which does not fit the context of animals processing time.
• conceive: 'Conceive' means to form or devise a plan or idea, which is not relevant to the action of sensing time.
• receive: 'Receive' means to get or be given something, which does not accurately describe the action of processing or sensing time.

Correct answer: presented

Explanation: The word 'presented' is the correct past tense verb that indicates Kevin Healy shared or displayed the results at a meeting. It fits grammatically and contextually as it describes an action that has already occurred, aligning with the past tense narrative of the sentence.

Meaning: 'Presented' means to show or display something formally, in this case, the results of the research at a meeting.

Wrong options:

• absented: 'Absented' means to be away or not present, which does not fit the context of sharing results.
• resented: 'Resented' means to feel bitterness or indignation at having been treated unfairly, which is irrelevant to the action of sharing results.
• assented: 'Assented' means to agree or express agreement, which does not match the context of presenting research findings.

Correct answer: began

Explanation: The word 'began' is the correct past tense form of the verb 'begin,' indicating that the action of reviewing research started in the past. It fits grammatically and contextually as it describes the initiation of their research process.

Meaning: 'Began' means to start or commence something, in this case, the review of previous research.

Wrong options:

• begun: 'Begun' is the past participle form of 'begin' and cannot stand alone without an auxiliary verb, making it grammatically incorrect here.
• brought: 'Brought' is the past tense of 'bring,' which does not convey the action of starting a review.
• has began: 'Has began' is grammatically incorrect as 'began' should be 'begun' when used with 'has,' making this option unsuitable.

Correct answer: passage

Explanation: The word 'passage' fits grammatically as it refers to the process of time moving forward. It aligns contextually with the sentence, which discusses how animals perceive the flow of time, making it the most appropriate choice.

Meaning: 'Passage' refers to the act of moving through or the process of time elapsing, which is relevant to the context of the flicker fusion test.

Wrong options:

• massage: 'Massage' refers to the act of kneading or rubbing the body, which is unrelated to the concept of time.
• message: 'Message' refers to a communication or information conveyed, which does not fit the context of time perception.
• paragraph: 'Paragraph' refers to a distinct section of writing, which is not relevant to the concept of time passing.