Also, making the ad look like the text is the doing of the site owner. There are people who will recommend you do that to increase click rates, but I don't think Google actively promotes that strategy.
The placement of the ad is also by the site owner. For my own site I chose to keep ads to the side bar. Admittedly Google keeps telling me that I could put more ads on my site, but I choose not to.
There is also perhaps an economics problem: perhaps most schools, being funded by public money, have no money for ads. What entities in the education market would spend big bucks on dinosaur ads? How can you make big money with dinosaurs?