For an older child, you could explain that the recipe for the apple ​ — in fact, for the entire tree on which it grew — ​ was part of the code in the DNA.
وَٱشْرَحْ لَهُ أَنَّ ٱلْوَصْفَةَ « مَكْتُوبَةٌ » دَاخِلَ ٱلْبِزْرَةِ ،‏ وَلٰكِنْ بِلُغَةٍ مُعَقَّدَةٍ أَكْثَرَ بِكَثِيرٍ مِنَ ٱلْوَصْفَةِ فِي كِتَابِ ٱلطَّبْخِ .‏