We need to arrange the sentences in a logical order to form a coherent paragraph. The correct order should present the topic, define it, explain its components, and discuss its consequences.
Step 1: Analyze each sentence.
- (1) introduces the concept of endangered languages, but it needs context for better understanding.
- (2) explains how languages are being replaced by others, which is a natural consequence of language extinction.
- (3) gives additional information about languages not being learned by the younger generation, indicating a further threat to language survival.
- (4) provides a definition of an endangered language, offering the fundamental explanation for the paragraph's topic.
- (5) talks about the consequence of language extinction, which follows naturally after the description of endangered languages.
Step 2: Organize logically.
The paragraph starts by defining an endangered language (4). Then, it discusses the trends of language extinction (2), followed by further elaboration on the lack of new speakers (3). The introductory sentence (1) provides a deeper example, and the paragraph concludes with a warning about language extinction (5).
Step 3: Conclusion.
The correct order is: 4 2 3 1 5.
Final Answer: (D) 4 2 3 1 5