The life cycles of many plants and animals are regulated by internal clocks. Many birds instinctively know when to begin their migration.
وَتُرَى أَيْضًا ٱلدِّقَّةُ فِي ٱلتَّوْقِيتِ فِي عَالَمِ ٱلْأَحْيَاءِ .‏