Meaning: 'Defects' refers to flaws or abnormalities, particularly in this context related to health issues such as microcephaly.

Wrong options:

• causing: The word 'causing' is a gerund that indicates an action but does not fit as a noun to describe health issues.
• range: The term 'range' refers to the extent or variety of something, which does not relate to health problems.
• rates: 'Rates' typically refers to measurements or statistics, which does not apply to the context of health defects.
• affording: 'Affording' is a verb that means to provide or supply, which does not fit the context of describing health issues.
• witness: The word 'witness' is a noun or verb that refers to seeing or experiencing something, which does not apply here.
• circulated: 'Circulated' is a verb that describes the action of moving around, which does not fit as a noun for health issues.

Correct answer: range

Explanation: The term 'range' is a noun that indicates the extent or variety of Zika's presence over time. It fits grammatically and contextually as it describes the scope of the virus's impact.

Meaning: 'Range' refers to the extent or variety of something, in this case, the duration and spread of the Zika virus.

Wrong options:

• causing: 'Causing' is a gerund that indicates an action but does not fit as a noun to describe the extent of the virus.
• defects: 'Defects' refers to health issues, which does not describe the extent or variety of Zika's presence.
• rates: 'Rates' refers to measurements or statistics, which does not apply to the context of describing the virus's presence.
• affording: 'Affording' is a verb that means to provide or supply, which does not fit the context of describing the extent of the virus.
• witness: 'Witness' does not relate to the extent or variety of the virus and is not appropriate in this context.
• circulated: 'Circulated' is a verb that describes the action of moving around, which does not fit as a noun for describing the virus's presence.

Correct answer: causing

Explanation: The word 'causing' is a gerund that indicates the action of bringing about health effects. It fits grammatically and contextually as it describes the virus's potential impact on health.

Meaning: 'Causing' refers to the act of bringing about or producing something, in this case, detrimental health effects.

Wrong options:

• defects: 'Defects' is a noun that describes health issues but does not fit grammatically as an action in this context.
• range: The term 'range' refers to the extent or variety of something, which does not apply to the action of producing health effects.
• rates: 'Rates' refers to measurements or statistics, which does not fit the context of describing an action related to health effects.
• affording: 'Affording' is a verb that means to provide or supply, which does not fit the context of describing an action related to health effects.
• witness: 'Witness' does not relate to the action of causing health effects and is not appropriate in this context.
• circulated: 'Circulated' is a verb that describes the action of moving around, which does not fit as an action related to health effects.

Correct answer: circulated

Explanation: The word 'circulated' is a verb that indicates the action of the virus moving through various locations. It fits grammatically and contextually as it describes the behavior of Zika over time.

Meaning: 'Circulated' refers to the act of moving around or spreading, in this case, the Zika virus in remote locations.

Wrong options:

• defects: 'Defects' is a noun that describes health issues, which does not fit as a verb describing the action of the virus.
• range: The term 'range' refers to the extent or variety of something, which does not apply to the action of the virus.
• rates: 'Rates' refers to measurements or statistics, which does not fit the context of describing the action of the virus.
• affording: 'Affording' is a verb that means to provide or supply, which does not fit the context of describing the action of the virus.
• witness: 'Witness' does not relate to the action of the virus and is not appropriate in this context.
• causing: 'Causing' is a gerund that indicates an action but does not fit as a verb describing the movement of the virus.