Meaning: 'Via' means 'by way of' or 'through,' indicating the method of collecting data from motion sensors.

Wrong options:

• of: The preposition 'of' indicates possession or belonging, which does not convey the method of data collection in this context.
• down: The word 'down' suggests a direction or position, which is irrelevant to the context of data collection.
• off: The word 'off' implies separation or disconnection, which does not fit the context of how data is gathered.

Correct answer: mortality

Explanation: The term 'mortality' refers specifically to the risk of death, making it the most appropriate choice in the context of predicting someone's risk of dying, aligning well with the overall topic of the sentence.

Meaning: 'Mortality' means the state of being subject to death; in this context, it refers to the risk of dying.

Wrong options:

• volatility: 'Volatility' refers to the tendency to change rapidly and unpredictably, which does not relate to the concept of death risk.
• notability: 'Notability' refers to the quality of being worthy of attention or notice, which is unrelated to mortality risk.
• compatibility: 'Compatibility' refers to the ability to exist or work together without conflict, which does not fit the context of risk assessment.

Correct answer: minority

Explanation: The word 'minority' indicates a smaller segment of a population, which is appropriate here as it describes the affluent group that primarily wears smartwatches and fitness trackers, fitting both grammatically and contextually.

Meaning: 'Minority' refers to a smaller part of a group, especially in terms of numbers or representation.

Wrong options:

• region: The word 'region' refers to a geographical area, which does not apply to the context of a demographic group wearing smartwatches.
• ethic: The term 'ethic' relates to moral principles, which is not relevant to the discussion of smartwatch ownership.
• majority: 'Majority' implies a larger segment of a population, which contradicts the context of the affluent group being a smaller segment.

Correct answer: alternative

Explanation: The word 'alternative' suggests a different option or substitute, which is fitting in the context of seeking a different predictor that can be measured with smartphones, aligning well with the sentence's intent.

Meaning: 'Alternative' means something that can be used instead of another; in this case, it refers to a different predictor for mortality risk.

Wrong options:

• allocated: The term 'allocated' refers to distributing resources or tasks, which does not fit the context of finding a predictor.
• alliterated: 'Alliterated' pertains to the repetition of initial consonant sounds, which is irrelevant in this context.
• alleviated: 'Alleviated' means to make something less severe, which does not relate to the search for a predictor.