A.I. Explanation:

Correct answer: integral

Explanation: The word 'integral' functions as an adjective that describes something essential or necessary. In this context, it indicates that good balance is a crucial component of physical fitness, aligning with the overall message of the sentence.

Meaning: 'Integral' means essential or necessary for completeness.

Wrong options:

• used: The word 'used' is a past participle that implies something has been utilized, which does not fit the context of describing balance as a necessary part of fitness.
• organic: The term 'organic' refers to something derived from living matter or relating to organic compounds, which does not convey the idea of necessity in this context.
• reference: The word 'reference' is a noun that denotes a mention or citation, which does not appropriately describe the role of balance in physical fitness.

Correct answer: affected

Explanation: The term 'affected' is the past participle of the verb 'affect,' indicating that older adults experience the impact of poor balance. This fits grammatically and contextually, as it describes the condition of older adults in relation to balance.

Meaning: 'Affected' means influenced or impacted by something.

Wrong options:

• used: The word 'used' does not fit here as it implies a completed action rather than a state of being influenced by poor balance.
• integral: The term 'integral' is an adjective that describes something essential, which does not apply to the state of older adults in this context.
• organic: The word 'organic' does not relate to the impact of balance on older adults and is irrelevant in this context.
• reference: The term 'reference' does not convey the idea of being influenced or impacted, making it unsuitable for this blank.

Correct answer: cause

Explanation: The word 'cause' serves as a noun that identifies the reason for something, in this case, the leading reason for injury and death among older adults. It fits grammatically and contextually, as it directly relates to the consequences of poor balance.

Meaning: 'Cause' refers to the reason or source of an event or condition.

Wrong options:

• used: The term 'used' does not fit as it implies a completed action rather than a reason for injury or death.
• integral: The word 'integral' describes something essential, which does not apply to the context of identifying a leading reason for injuries.
• organic: The term 'organic' does not relate to the concept of causation and is irrelevant in this context.
• reference: The word 'reference' is a noun that denotes a mention or citation, which does not appropriately describe the leading reason for injuries.