First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic of the text. It talks about the invention of electronic devices, which is a broad overview of the subject. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs are not chosen because they do not stand alone. For example, Paragraph 2 starts with 'Such as', which is a connector. Paragraph 3 starts with 'But', which is also a connector. Paragraph 4 talks about the amount of e-waste but does not introduce the main topic.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it provides a summary of the problem discussed. It gives a clear fact about e-waste growth, which wraps up the topic. This follows the Summary Style rule.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it gives examples of electronic devices. This follows the Broader to Specific Strategy. The first paragraph is general, and the second gives specific examples.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it talks about a problem related to the examples given. This follows the Logical Order rule, as it moves from examples to a related issue.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it gives information about the growth of e-waste. This follows the Cause and Effect Relationship rule, as it explains why dealing with e-waste is a problem.