A.I. Explanation:

First sentence: Why this is the first line? This paragraph is the first sentence because it introduces the main topic, which is the flower called Goldfields. It gives a clear overview of what the text is about without needing other sentences for context. This follows the rule of Topic Sentence. Why other lines are not chosen? The other paragraphs do not qualify as the first sentence. For example, Paragraph 2 starts with 'Covering', which is a transitional phrase. Paragraph 3 starts with 'The low-growing plant', which uses 'the' and assumes prior knowledge. Paragraph 4 starts with 'Horses graze', which also assumes knowledge of the topic.

Concluding sentence: Why this is the last line? This paragraph is the last sentence because it wraps up the information about the flower. It gives a final detail about the flower's name and what happens to it. This follows the rule of Summary Style.

Paragraph pairs:

• Pair 1 (Paragraph 1 → Paragraph 2): Paragraph 2 connects to Paragraph 1 because it continues to talk about the flower. It uses the phrase 'this flower', which refers back to Goldfields. This follows the Noun Pronoun Rule.
• Pair 2 (Paragraph 2 → Paragraph 3): Paragraph 3 connects to Paragraph 2 because it gives more details about the flower. It explains what the flower looks like and when it blooms. This follows the Broader to Specific Strategy.
• Pair 3 (Paragraph 3 → Paragraph 4): Paragraph 4 connects to Paragraph 3 because it talks about what happens to the blossoms. It explains that horses eat the blossoms and mentions a fly. This follows the Logical Order.