Five jumbled up sentences (labelled 1, 2, 3, 4 and 5), related to a topic, are given below. Four of them can be put together to form a coherent paragraph. Identify the odd sentence and key in the number of that sentence as your answer.

The correct answer is:
"When more people use buses or trains the service usually improves because public-transport agencies run more buses and trains."

Step-by-step Explanation:

To identify the odd sentence, we need to analyze the theme of the sentences and find the logical sequence that forms a coherent paragraph among four of them.

Step 1: Identify the central theme
If we look at the sentences, most of them discuss the decline in the use of urban public transport in Western countries and explore the reasons behind this trend (such as lifestyle changes, technology, and alternative options like ride-sharing or dockless bikes).

Step 2: Connect the sentences to form a coherent chain
Let's see how four of the sentences link together logically:

• Sentence 5: "There has been a puzzling decline in the use of urban public transport in many countries in the west..."
  This sentence introduces the main topic/phenomenon (the decline in public transport usage) and serves as the perfect opening sentence.
• Sentence 3: "Worsening services on public transport, terrorist attacks in some urban metros and a rise in fares have been blamed for this trend."
  This directly follows Sentence 5, explaining the common reasons blamed for "this trend" (the decline).
• Sentence 4: "It seems more likely that public transport is being squeezed structurally as people’s need to travel is diminishing..."
  This sentence offers a counter-perspective or a deeper reason for the decline, suggesting structural factors like remote work and online shopping.
• Sentence 1: "Urbanites also have more and better options for getting around: Uber is ubiquitous; easy-to-rent dockless bicycles are spreading..."
  The word "also" connects this directly to Sentence 4, providing additional structural reasons (alternative mobility options) contributing to the decline.

Step 3: Identify the odd sentence
Sentence 2 ("When more people use buses or trains the service usually improves because public-transport agencies run more buses and trains.") describes a general positive relationship between public transport ridership and service quality. It does not fit into the discussion of the declining transport usage trend or its causes. Therefore, it is the odd sentence out.