A: I'm sure you don't start off that way. You point is vague.
Two people see the same event and write stories A and B about it. Both contain similar things but differ in language and subtle content.
5 years later someone comes along to write about the same event. They see books A and B - and so use both books to write their account - story C.
Now A and B will only contain similar details for the largest things (the actual event happening etc). and will differ on the small detail (what they were doing at the time etc)
C uses all of A and B - so of course A will be included in C, as will B.
Because C was written later in time it can use all of the bits of A and B and combine them - thus being far closer to A or to B than A is to B.
If you can not understand this then please just accept that you're wrong and move along.
B: It is a historical Fact that the flood occured. The correlation with hundreds of alike stories around the earth make it a corelated event. Which is what is nescessary to make it apart of history?
I suggest that you do a course in (a) history, and (b) logical fallacies.
The entire world could say that all the animals went two by two into the ark - yet it wouldn't be true (partly 'cos clean animals went in to the ark in 7s - not 2s!).
The entire world could think that Alpha Centaurii is the closest star to Earth - but it wouldn't be true (our sun is!).
Furthermore - stories do NOT constitute sufficient evidence to make something fact - no matter how rife they are throughout culture.
If culture A wrote about a local flood in the year 10,000 BC, and culture B wrote about a local flood that occured in 8,000 BC - but the two stories were only found in writings from 3,000 BC it is quite possible that one could claim there was at one point in history a world-wide flood. Yet the local floods occurred 2,000 years apart.
You do need to support your claims.
In some way.
Any way.
Any way at all.
Just a bit.