Meaning: To 'monitor' means to observe and check the progress or quality of something over a period of time.

Wrong options:

• utilize: The word 'utilize' is a verb that means to make use of something, but it does not fit the context of directly observing health.
• identify: The word 'identify' is a verb that means to recognize or establish what something is, which does not relate to the action of monitoring health.
• pragmatic: The word 'pragmatic' is an adjective that refers to dealing with things sensibly and realistically, which does not fit as a verb in this context.
• commercial: The word 'commercial' is an adjective that describes something related to commerce, which does not fit as an action related to health monitoring.
• specialize: The word 'specialize' is a verb that means to focus on a particular area, which does not fit the context of monitoring health directly.

Correct answer: utilize

Explanation: The term 'utilize' is a verb that fits grammatically and contextually as it describes how patients make use of the optical technique for monitoring health.

Meaning: To 'utilize' means to make practical and effective use of something.

Wrong options:

• monitor: The word 'monitor' is already used in the first blank and does not fit here as it would create redundancy.
• identify: The word 'identify' does not fit as it implies recognition rather than the act of using a technique.
• pragmatic: The word 'pragmatic' is an adjective and does not fit as a verb in this context.
• commercial: The word 'commercial' is an adjective that does not fit as it does not describe an action related to using a technique.
• specialize: The word 'specialize' implies focusing on a specific area, which does not fit the context of using a technique.

Correct answer: commercial

Explanation: The word 'commercial' is an adjective that fits grammatically and contextually as it describes health monitoring devices that are available in the market.

Meaning: 'Commercial' refers to something that is related to or engaged in commerce, typically available for sale.

Wrong options:

• utilize: The word 'utilize' is a verb and does not fit as an adjective to describe devices.
• identify: The word 'identify' is a verb that does not fit as it does not describe a type of device.
• pragmatic: The word 'pragmatic' is an adjective that does not specifically describe health monitoring devices.
• practical: The word 'practical' is an adjective that describes usability but does not indicate the commercial aspect of the devices.
• specialize: The word 'specialize' is a verb and does not fit as an adjective to describe devices.

Correct answer: practical

Explanation: The word 'practical' is an adjective that fits grammatically and contextually as it describes the usability of the PPG technique for users.

Meaning: 'Practical' refers to something that is useful and sensible in real situations.

Wrong options:

• utilize: The word 'utilize' is a verb and does not fit as an adjective to describe the usability of the technique.
• identify: The word 'identify' is a verb that does not describe the usability of the technique.
• pragmatic: The word 'pragmatic' is an adjective that means dealing with things sensibly, but it does not specifically convey the usability aspect as effectively as 'practical.'
• commercial: The word 'commercial' describes a market aspect and does not relate to usability for users.
• specialize: The word 'specialize' is a verb and does not fit as an adjective to describe the usability of the technique.