Meaning: 'Involved' means to be engaged or participating in something, in this case, memory and learning.

Wrong options:

• explained: 'Explained' is a past participle that does not fit grammatically as it does not describe a state of being related to the brain's functions.
• release: 'Release' is a verb that does not describe the state of the brain areas and is not appropriate in this context.
• causing: 'Causing' is a gerund that implies an action rather than a state, which does not fit the grammatical structure here.
• consideration: 'Consideration' is a noun that does not describe the areas of the brain and does not fit grammatically.

Correct answer: release

Explanation: The term 'release' is a noun that refers to the act of letting go or discharging something, in this case, chemicals. It fits grammatically as it serves as the subject of the clause and aligns with the context of discussing the effects of exercise on brain chemistry.

Meaning: 'Release' refers to the act of allowing something to escape or be set free, particularly in the context of chemicals in the brain.

Wrong options:

• reducing: 'Reducing' is a gerund that implies an action rather than a noun, which does not fit the grammatical structure here.
• impact: 'Impact' is a noun that does not describe the act of discharging chemicals and is not appropriate in this context.
• involved: 'Involved' is an adjective that does not fit as it does not describe an action or process related to chemical discharge.
• explained: 'Explained' is a past participle that does not fit grammatically as it does not describe an action related to the release of chemicals.

Correct answer: impact

Explanation: The word 'impact' is a noun that refers to the effect or influence of one thing on another. It fits grammatically as it serves as the object of the preposition 'on' and aligns with the context of discussing the effects of chemicals on brain cells.

Meaning: 'Impact' refers to the strong effect or influence that something has on a situation or person, in this case, the health of brain cells.

Wrong options:

• release: 'Release' is a noun that describes an action rather than an effect, which does not fit the grammatical structure here.
• reducing: 'Reducing' is a gerund that implies an action rather than a noun, which does not fit in this context.
• involved: 'Involved' is an adjective that does not describe an effect and is not appropriate here.
• explained: 'Explained' is a past participle that does not fit grammatically as it does not describe an effect on brain cells.

Correct answer: reducing

Explanation: The term 'reducing' is a gerund that describes the action of making something smaller or less in amount, degree, or size. It fits grammatically as it serves as the object of the verb 'helps' and aligns with the context of discussing how exercise aids brain function by lowering stress and anxiety levels.

Meaning: 'Reducing' means to make something less in quantity, degree, or size, particularly in the context of stress and anxiety.

Wrong options:

• release: 'Release' is a noun that does not describe an action related to helping the brain function and does not fit grammatically.
• impact: 'Impact' is a noun that does not describe an action and is not appropriate in this context.
• involved: 'Involved' is an adjective that does not describe an action and does not fit grammatically here.
• explained: 'Explained' is a past participle that does not fit as it does not describe an action related to stress reduction.