Subject: Experiement: bread mold?

Experiement: bread mold?
This is for my daughter, Amanda.  She is doing a science
project on bread mold (white, wheat & rye).  She thought that mold
would grow on white bread first, but it didn't. Mold has been on the
rye bread after only 6 days.  Since she has chosen three breads, not
only one--she has to give the reason why did mold grow on rye bread
first.  She thought, that a preservative maybe the reason that
rye has that white or wheat does not.  One of the ingredients in both
white and wheat is active dry yeast (rye does not).  Could this be
a conclustion for why rye grew mold MUCH faster.  She also has to 
have info on mold itself.  The conditions of the mold growing are:
1.  She used a cotton swab and put dust onto each slice of bread
2.  She put each piece of bread in a plastic bag
3.  She put all three pieces in a tupperware container 
   and kept in a closed drawer.  Thank you very much!

Re:Experiement: bread mold?