Meaning: 'Worldwide' means 'throughout the world' or 'global', indicating that orangutans are found in many places around the world.

Wrong options:

• everywhere: While 'everywhere' suggests a similar meaning, it is more informal and does not fit the formal tone of the text as an adverb in this context.
• widespread: This term implies a broad distribution but lacks the global connotation that 'worldwide' provides, making it less precise in this context.
• blockbusters: This option refers to successful films and does not relate to the geographical presence of orangutans, making it irrelevant.

Correct answer: which

Explanation: The word 'which' is a relative pronoun that introduces a non-defining clause, providing additional information about 'the orang-utan'. It fits grammatically and contextually, linking the definition of the term to the subject.

Meaning: 'Which' is used to introduce a clause that gives more information about something previously mentioned, in this case, the orang-utan.

Wrong options:

• it: This pronoun would imply a subject change and does not introduce additional information, making it grammatically incorrect here.
• that: While 'that' could introduce a defining clause, it does not fit the non-defining context of the sentence, which requires 'which'.
• usually: This adverb does not function as a pronoun and does not fit grammatically in this context.

Correct answer: the only

Explanation: The phrase 'the only' correctly emphasizes the uniqueness of the orang-utan as the sole great ape in Asia. It fits grammatically as a determiner and contextually highlights its singular status among great apes.

Meaning: 'The only' means 'the single one' or 'no others', indicating that the orang-utan is the sole representative of great apes in Asia.

Wrong options:

• exclusively: This adverb suggests limitation but does not convey the idea of singularity as effectively as 'the only'.
• one: This numeral lacks the definitive emphasis needed in this context, making it less appropriate than 'the only'.
• similar: This adjective implies likeness but does not convey the uniqueness required in this context.

Correct answer: why

Explanation: The word 'why' serves as a conjunction introducing a clause that explains the reason behind the Malays' naming of the orang-utan. It fits grammatically and contextually as it seeks to clarify the rationale.

Meaning: 'Why' is used to ask for reasons or explanations, making it suitable for the context of understanding the naming of the orang-utan.

Wrong options:

• because: This conjunction introduces a reason but does not fit grammatically as it would require a complete clause following it, making it incorrect here.
• the reason for: This phrase is unnecessarily verbose and does not fit the grammatical structure of the sentence, which requires a simpler conjunction.
• explanation: This noun does not function as a conjunction and cannot grammatically fit into the sentence.

Correct answer: incredibly

Explanation: The adverb 'incredibly' modifies the adjective 'human', emphasizing the extent to which orangutans exhibit human-like behavior. It fits grammatically and contextually, enhancing the description of their behavior.

Meaning: 'Incredibly' means 'extremely' or 'unbelievably', indicating a high degree of similarity to human behavior.

Wrong options:

• invariably: This adverb suggests something that is always the case, which does not fit the context of describing behavior that can vary.
• impossibly: This adverb implies something that cannot happen, which contradicts the intended meaning of highlighting similarities to humans.
• increasingly: This adverb suggests a gradual change over time, which does not accurately describe the current state of orangutan behavior.

Correct answer: up to

Explanation: The phrase 'up to' indicates a maximum limit, fitting grammatically and contextually as it describes the weight an orang-utan can reach. It aligns with the structure of the sentence, which discusses the weight of orangutans.

Meaning: 'Up to' means 'as much as' or 'not exceeding', indicating the maximum weight an orang-utan can attain.

Wrong options:

• totally: This adverb implies completeness but does not convey the idea of a maximum limit, making it inappropriate in this context.
• heavier than: This comparative phrase does not fit grammatically as it requires a comparison, which is not present in the sentence structure.
• always: This adverb suggests constancy, which does not apply to the context of weight that can vary.