Allah is the One Who created you from weakness, then made after weakness strength, then made after strength weakness and white hair; He creates what He wishes, and He is the Capable Knower of everything.
Lord created and brought up mankind by passing through different stages in the womb, then bringing out from the womb of the mother, then laying, kneeling, and walking with and without support, and become matured and puberty, and after marriage by sexual intercourse reproduction is happening, and after some years becoming old, and when he is in the utmost of old age, his nature becomes just like that of a child as told in verse 36: 68. Compared to all other creatures man is born weak. The human baby even can’t breastfeed himself or herself. See explanation 16: 70 and 22: 5.