Given below is a statement followed by two assumptions numbered I and II. Statement: The railway authority has announced that it will carry out major repair work for two days beginning Saturday on the main line connecting two big cities in the state, bringing the rail service to a halt. Assumptions: I. People may reschedule their journey in view of the railway authority's decision. II. People may still plan their travel by train between the two cities even on these two days. Identify which of the given assumption(s) is/are implicit in the statement.

Identify which of the assumptions must hold for the statement to be valid. Statement: Urban sprawl, which leads to the expansion of cities into rural areas, often results in the loss of biodiversity, fragmentation of ecosystems, and increased pollution, thereby posing a significant challenge to sustainable development. Assumptions: I. Urban sprawl contributes to the degradation of natural ecosystems. II. Sustainable development can be achieved without considering the impact of urbanization on ecosystems. III. The expansion of cities results in the destruction of biodiversity and environmental degradation.