The true statement about the length of days and nights in spring is that the days become longer and the nights become shorter. During spring, the tilt of the Earth's axis causes the Sun to move higher in the sky, resulting in longer daylight hours. This is particularly evident at higher latitudes. As spring progresses, the amount of daylight gradually increases, leading to longer days. Conversely, the nights become shorter as the daylight hours extend. This change in daylight and darkness is a characteristic of the seasonal transition from winter to spring.