Both Statement I and Statement II are correct, and Statement II explains Statement I due to the differential heating properties of land and water. In January, landmasses typically cool down more rapidly than oceans, resulting in colder air over land as opposed to warmer air over the oceans. This temperature gradient causes isotherms to bend equatorward over cooler land and poleward over the warmer oceans, as the warmer air over the oceans tends to rise and modify the temperature profile in the atmosphere. This concept illustrates the fundamental principles of atmospheric dynamics and thermal contrasts, which are essential for understanding weather patterns and climate in the context of geography and climatology as outlined in UPSC resources.