Meaning: 'Ought' means 'should' or 'is expected to,' indicating a strong recommendation for having hobbies to be happy and safe.

Wrong options:

• will: 'Will' indicates future intention but does not convey obligation or recommendation, making it less suitable in this context.
• must: 'Must' implies a strong necessity, which is too forceful for the advice being given here.
• should: 'Should' is similar to 'ought' but is less formal; 'ought' is more appropriate in this context.

Correct answer: aggravates

Explanation: The word 'aggravates' fits well as it means to make a situation worse, which aligns with the context of increasing mental strain. It is grammatically correct as it matches the subject of the sentence and conveys the intended meaning.

Meaning: 'Aggravates' means to worsen or intensify a problem, indicating that starting late in life increases mental strain.

Wrong options:

• makes: 'Makes' is too vague and does not convey the negative impact implied in the sentence.
• initiate: 'Initiate' means to begin something, which does not fit the context of increasing strain.
• deteriorates: 'Deteriorates' implies a decline but does not specifically convey the idea of worsening strain as effectively as 'aggravates'.

Correct answer: acquire

Explanation: The word 'acquire' is appropriate as it means to gain or obtain knowledge, fitting grammatically and contextually with the idea of gaining knowledge unrelated to daily work.

Meaning: 'Acquire' means to gain or obtain something, in this case, knowledge of various topics.

Wrong options:

• lose: 'Lose' is the opposite of what is intended, as it implies a reduction in knowledge rather than gaining it.
• deny: 'Deny' does not fit contextually, as it suggests refusing something rather than gaining knowledge.
• move: 'Move' is unrelated to the context of gaining knowledge and does not fit grammatically.

Correct answer: Broadly

Explanation: The word 'Broadly' is suitable as it indicates a general perspective, fitting grammatically and contextually with the classification of human beings into three classes.

Meaning: 'Broadly' means in general terms or overall, suggesting a wide perspective on human classification.

Wrong options:

• Calmly: 'Calmly' refers to a manner of doing something and does not fit the context of categorization.
• Mainly: 'Mainly' suggests a focus on the primary aspect, which is too narrow for the general classification intended here.
• Only: 'Only' restricts the scope and does not convey the intended broad categorization of human beings.