Meaning: To 'flash' back means to suddenly remember something vividly, often in a brief moment.

Wrong options:

• equivalent: 'Equivalent' is an adjective that means equal in value or meaning, which does not fit the context of recalling a memory.
• ago: 'Ago' is an adverb that indicates a time in the past, but it does not function as a verb to describe the action of recalling.
• prior: 'Prior' is an adjective that refers to something that came before, but it does not convey the action of recalling a memory.
• last: 'Last' is an adjective that refers to the most recent in time, which does not fit as a verb in this context.
• latter: 'Latter' is an adjective that refers to the second of two items mentioned, which does not fit as a verb for recalling a memory.
• exclusive: 'Exclusive' is an adjective that means limited to a particular group, which does not fit the context of memory recall.

Correct answer: prior

Explanation: The term 'prior' is used as an adjective to indicate something that occurred before another event, in this case, the visit to a friend's house. It fits grammatically and contextually as it describes the timing of the week in relation to the visit.

Meaning: 'Prior' means earlier in time or before something else.

Wrong options:

• equivalent: 'Equivalent' is an adjective that means equal in value or meaning, which does not fit the context of time reference.
• ago: 'Ago' is an adverb that indicates a time in the past but does not function as an adjective to describe the week.
• flash: 'Flash' is a verb that does not relate to the timing of events and does not fit in this context.
• last: 'Last' is an adjective that refers to the most recent, which does not accurately describe the week before the visit.
• latter: 'Latter' is an adjective that refers to the second of two items mentioned, which does not fit as it does not describe the timing of the week.
• exclusive: 'Exclusive' is an adjective that means limited to a particular group, which does not fit the context of time.

Correct answer: latter

Explanation: The word 'latter' is used to refer to the second of two items mentioned, which in this case is the type of memory that allows people to revisit past experiences. It fits grammatically and contextually as it distinguishes between two types of memory discussed in the text.

Meaning: 'Latter' refers to the second of two things previously mentioned.

Wrong options:

• equivalent: 'Equivalent' is an adjective that means equal in value or meaning, which does not fit as it does not refer to a type of memory.
• ago: 'Ago' is an adverb that indicates a time in the past, which does not fit as it does not describe a type of memory.
• prior: 'Prior' is an adjective that refers to something that came before, which does not fit as it does not refer to the second type of memory.
• flash: 'Flash' is a verb that does not relate to the classification of types of memory and does not fit grammatically.
• last: 'Last' is an adjective that refers to the most recent, which does not fit as it does not describe a type of memory.
• exclusive: 'Exclusive' is an adjective that means limited to a particular group, which does not fit as it does not describe a type of memory.

Correct answer: exclusive

Explanation: The term 'exclusive' is used as an adjective to describe the belief that episodic memory was thought to be limited to humans. It fits grammatically and contextually as it conveys the idea of something being restricted to a particular group.

Meaning: 'Exclusive' means limited to a particular group or not shared with others.

Wrong options:

• equivalent: 'Equivalent' is an adjective that means equal in value or meaning, which does not fit the context of describing a belief about memory.
• ago: 'Ago' is an adverb that indicates a time in the past, which does not fit as it does not describe a belief or characteristic.
• prior: 'Prior' is an adjective that refers to something that came before, which does not fit in this context as it does not describe exclusivity.
• flash: 'Flash' is a verb that does not relate to the concept of exclusivity and does not fit grammatically.
• last: 'Last' is an adjective that refers to the most recent, which does not fit as it does not describe a belief about memory.
• latter: 'Latter' is an adjective that refers to the second of two items mentioned, which does not fit as it does not describe exclusivity.