1 blog 3 different ads is it illegal?

i created 4 blogs right now.. i put 3 different ads for each blog is it ok?
adsense, infolinks, and bidvertiser.. thanks for the help!

my blogs are about educational science blogs..
if you're curious here's my 4 blogs (no spam)

http://adf.ly/2GsoN - http://footkablog.blogspot.com/
http://adf.ly/2NzMu - http://spacescience-era.blogspot.com/
http://adf.ly/2SZum - http://earth-science-era.blogspot.com/
http://adf.ly/2fxuw - http://animal-world-era.blogspot.com/