how did the man made religion of christiantiy lead to modern science?

Some scientist read that "Life is in the blood", Gen. 9:4, Lev. 17:11 Medical science came to that realization, and modified the practice of "bleeding".

Since Christianity isn't man-made, you have no question.

China was the first modern state they invented rockets, silk printing and so much more but their society collapsed!

In many ways the reason industry rose in the west was that whilst printing presses and other things had been invented two world wars destroyed almost all manufacturing places and the production of armaments introduced new materials and ways of working!

Jesus personally established Christianity--Catholicism in particular. A person can know these things with certainty by reciting the rosary every day with care.

they did in fact have what we would call science or early versions of it. Also, it's a case of history being written in favor of the victors.

Jesus the Christ was foretold for about 5 generations or more.

Paul was selected by Jesus.

Men don't like Christianity, so they sure didn't make it up.

It's for Salvation.

There is science but not key.

It didn't. I've read some of the "medieval philosophy" on the possible existence of 'god', and none of them had anything to do with Christianity. Leibniz, Descartes and Newton all wrote about some vague concept of a supreme being, but the 'god' they're referring to sound nothing like Christianity's Jeebus or their invisible sky daddy.

I will admit that Christianity had its uses at one point in time. It served to unite Europe, so that Europeans could throw off the shackles of superstition such as Christianity.