No amount of scientific explanation can exhaustively explain a phenomenon. Feynman puts this nicely with the story of "Why did aunt slipped and fell down" in his talk about magnetism.

For instance we know that the life forms grow via cell division, but no text can address the question of "why". They can only talk about "how".

Infact, science quest is not really about answering "why" all the way down the causal chain. It is about learning how the qualities of things are related and a bit of shallow causal chain inspection.

The causal chain, by nature, does not allow full inspection. It's dependency on temporal constructs means it breaks down where time breaks down. Infact causality might might break down at macro levels as well, leading to loops with no end or beginning (kind of chicken and egg problem).