[jack_ (OP)]

Joe wants to know more about DNA:

How is it possible for four proteins to contain the instructions for a living organism given the diversity of cells (brain, placenta, eyes, producing gastric acid, timing of the release of hormones (how do “they” know it’s time for puberty), etc.

Do you have an answer that might help?

[RD]

How is it possible for four proteins to contain the instructions for a living organism given the diversity of cells ...

In a similar way that a binary-code only consisting of 1's & 0's can represent any computer-data:
 e.g. pictures, documents, sound-recordings, movies, software.

[ genetic code is triplet code rather than binary, but the same principle applies  ]

[syhprum]

DNA does not of course contain any proteins just the instructions for making them