A.I. Explanation:

Correct answer: interested

Explanation: The word 'interested' is an adjective that describes the subject 'those' in the sentence, indicating their engagement or curiosity about human thought and behavior. This fits grammatically as it complements the noun phrase and aligns with the context of discussing suitability for a course.

Meaning: 'Interested' means having a desire to learn or know about something.

Wrong options:

• practised: Practised is the past tense of practice, which does not fit here as it does not describe a state of curiosity or engagement.
• defined: Defined is a verb that does not fit grammatically as it does not describe the subject's state of interest.
• affected: Affected is a verb that implies influence, which does not relate to the subject's engagement with the course.
• applied: Applied is a verb that indicates action, which does not describe the state of being interested.
• diagnosed: Diagnosed is a verb that refers to identifying a condition, which does not fit the context of expressing interest.

Correct answer: defined

Explanation: The term 'defined' is a verb that fits grammatically as it describes the action of explaining what psychology is. It aligns with the context of providing a clear explanation of the subject matter.

Meaning: 'Defined' means to explain the meaning of something clearly and precisely.

Wrong options:

• practised: Practised does not fit as it refers to the act of doing something repeatedly, which does not apply to defining a subject.
• interested: Interested is an adjective that does not fit as it does not describe an action related to defining.
• affected: Affected is a verb that implies influence, which does not relate to the act of defining psychology.
• applied: Applied is a verb that indicates action but does not fit in the context of defining a subject.
• diagnosed: Diagnosed is a verb that refers to identifying a condition, which does not apply to the definition of psychology.

Correct answer: applied

Explanation: The word 'applied' is a past participle that fits grammatically as it describes how the approaches to psychology are utilized in various fields. This aligns with the context of discussing practical applications of psychological theories.

Meaning: 'Applied' means to put something into practice or use in a specific context.

Wrong options:

• practised: Practised does not fit as it refers to the act of doing something repeatedly, which does not describe the utilization of approaches.
• defined: Defined is a verb that does not fit in this context as it does not describe the action of using approaches.
• affected: Affected is a verb that implies influence, which does not relate to the application of approaches.
• interested: Interested is an adjective that does not describe the action of applying approaches to areas of study.
• diagnosed: Diagnosed is a verb that refers to identifying a condition, which does not apply to the application of psychological approaches.