English Language · English

Five 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 which does not fit into the coherent theme of the paragraph. 1: This paradox, known as the grandfather paradox, demonstrates the inherent logical contradiction that arises if time travel to the past were physically possible. 2: Relativity, particularly the theory of general relativity, does not explicitly forbid time travel, suggesting the potential for 'closed timelike curves' in certain extreme gravitational conditions. 3: However, for such theoretical pathways to be realized, they would necessitate the existence of exotic matter with negative mass or energy, which has yet to be observed. 4: The most plausible form of time travel, according to current physics, is forward-only, achievable simply by traveling at speeds approaching the speed of light. 5: Quantum mechanics governs the behavior of subatomic particles, dealing with probabilities rather than certain, predictable outcomes.