4

Set 11: Form, Structure & Sense (Intermediate)

Explanation

Answer: B

PASSAGE

The Amazon rainforest produces approximately 20% of the world's _______ making it critical for global climate stability.

Which choice completes the text so that it conforms to the conventions of Standard English?

A. oxygen;
B. oxygen,✓ Correct
C. oxygen
D. oxygen:

Detailed Answer Explanation

This question tests your understanding of sentence function and text organization. A comma is needed before the participial phrase 'making it critical.' This phrase modifies the main clause and should be set off by a comma. Each sentence in a well-constructed text serves a specific purpose. Consider what role this sentence plays in the argument: does it introduce, support, contrast, or conclude an idea? Understanding why an author includes specific sentences helps you grasp the overall argument. Each sentence should serve a clear purpose: introducing ideas, providing evidence, acknowledging counterarguments, or drawing conclusions. Identify the role to understand the structure.

Key Evidence:

• "produces approximately 20%"

• "making it critical"

Why others are wrong: C (Without punctuation, the sentence runs together incorrectly.), A (A semicolon is used between independent clauses; 'making it critical' is not independent.), D (A colon would introduce a list or explanation, not a participial phrase.).

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