Daylength refers to the duration of time between sunrise and sunset. It varies throughout the year due to the tilt of the Earth's axis and its orbit around the Sun. During summer, days are longer, while in winter, they are shorter. The change in daylength affects various natural processes, including the behavior of plants and animals. For example, many plants rely on longer days to trigger flowering, while some animals may adjust their breeding cycles based on the amount of daylight they receive.