Meaning: 'Mental disorders' refer to a range of psychological conditions that affect mood, thinking, and behavior.

Wrong options:

• memory: Memory is a noun that refers to the ability to store and recall information, which does not fit the context of reducing symptoms related to mental health issues.
• natural: Natural is an adjective that describes something occurring in nature, which does not fit as it does not describe a type of disorder.
• stress: Stress is a noun that refers to a state of mental or emotional strain, but it is not a disorder itself and does not fit the grammatical structure here.
• sleep: Sleep is a noun that refers to a natural state of rest, which is unrelated to the context of mental health disorders.
• concentration: Concentration is a noun that refers to the ability to focus attention, which does not relate to the reduction of mental health symptoms.
• resilience: Resilience is a noun that refers to the ability to recover from difficulties, but it does not describe a disorder.

Correct answer: natural

Explanation: The word 'natural' is an adjective that describes the noun 'antidepressant.' It fits grammatically and contextually, as it emphasizes that exercise is a non-pharmaceutical way to improve mood.

Meaning: 'Natural' refers to something that exists in nature and is not artificial or synthetic.

Wrong options:

• memory: Memory is a noun and does not fit grammatically as it cannot describe an antidepressant.
• stress: Stress is a noun that does not function as an adjective and does not describe the type of antidepressant.
• sleep: Sleep is a noun that cannot describe an antidepressant and is unrelated to the context of exercise as a mood enhancer.
• concentration: Concentration is a noun that does not fit as it cannot describe an antidepressant.
• mental disorders: Mental disorders is a noun phrase that does not fit grammatically as it cannot describe an antidepressant.
• resilience: Resilience is a noun that cannot function as an adjective to describe an antidepressant.

Correct answer: concentration

Explanation: The word 'concentration' is a noun that fits grammatically as the object of the verb 'leading to.' It is contextually appropriate as it relates to the cognitive benefits of exercise, specifically the ability to focus.

Meaning: 'Concentration' refers to the ability to focus one's attention on a particular task or subject.

Wrong options:

• memory: Memory is a noun that refers to the ability to recall information, but it does not fit the context of cognitive function enhancement as directly as concentration does.
• natural: Natural is an adjective and does not fit grammatically as it cannot serve as the object of the verb in this context.
• stress: Stress is a noun that does not relate to cognitive function and does not fit grammatically in this context.
• sleep: Sleep is a noun that refers to a state of rest and does not fit as a measure of cognitive function.
• mental disorders: Mental disorders is a noun phrase that does not fit as it does not relate to cognitive function but rather to psychological conditions.
• resilience: Resilience is a noun that refers to the ability to recover from difficulties, which does not directly relate to cognitive function.

Correct answer: resilience

Explanation: The word 'resilience' is a noun that fits grammatically as the object of the verb 'improving.' It is contextually relevant as it describes the long-term benefits of exercise on mental health, particularly in managing stress and overcoming challenges.

Meaning: 'Resilience' refers to the capacity to recover quickly from difficulties or adapt to change.

Wrong options:

• memory: Memory is a noun that does not fit as it does not relate to long-term mental health benefits in the context provided.
• natural: Natural is an adjective and does not fit grammatically as it cannot serve as the object of the verb in this context.
• stress: Stress is a noun that does not fit as it does not describe a quality that can be improved through exercise.
• sleep: Sleep is a noun that refers to a state of rest and does not relate to resilience or mental health management.
• concentration: Concentration is a noun that refers to focus and does not fit as a measure of long-term mental health benefits.
• mental disorders: Mental disorders is a noun phrase that does not fit as it does not describe a quality that can be improved.