Meaning: 'Forge' means to create or develop something, especially with effort, in this case, new relationships.

Wrong options:

• complete: The word 'complete' is an adjective that does not fit grammatically as it does not indicate an action related to relationships.
• involvement: 'Involvement' is a noun that does not fit the grammatical structure needed here, as it does not convey an action.
• state: 'State' is a noun that does not indicate an action and does not fit the context of forming relationships.

Correct answer: last

Explanation: The verb 'last' is used here to indicate the duration of behaviors learned during adolescence. It fits grammatically as it is in the base form, which is appropriate following the auxiliary verb 'will' in this context.

Meaning: 'Last' means to continue for a specified period of time, in this case, throughout their lives.

Wrong options:

• forge: 'Forge' is a verb that does not fit in this context as it does not relate to the duration of behaviors.
• complete: 'Complete' is an adjective that does not convey the idea of duration and does not fit grammatically.
• involvement: 'Involvement' is a noun that does not indicate an action related to the duration of behaviors learned.
• state: 'State' is a noun that does not fit the grammatical structure needed here, as it does not convey an action.

Correct answer: transition

Explanation: The noun 'transition' refers to the process of changing from one state to another, which is appropriate in the context of moving from childhood to adulthood. It fits grammatically as it serves as the subject of the sentence.

Meaning: 'Transition' means the process or period of changing from one state or condition to another.

Wrong options:

• complete: 'Complete' is an adjective that does not fit as it does not describe a process or period.
• involvement: 'Involvement' is a noun that does not accurately describe the change from childhood to adulthood.
• state: 'State' is a noun that does not convey the idea of a process or change.

Correct answer: range

Explanation: The noun 'range' is used here to indicate a variety or spectrum of health risks faced during adolescence. It fits grammatically as it serves as the subject of the sentence, describing the types of risks.

Meaning: 'Range' refers to a variety or selection of different things, in this case, health risks.

Wrong options:

• complete: 'Complete' is an adjective that does not fit as it does not describe a variety of risks.
• involvement: 'Involvement' is a noun that does not accurately describe the types of health risks.
• state: 'State' is a noun that does not convey the idea of a variety or spectrum.