scientists and the frog

in a laboratory , A team of scientists decided to do some experiments on a frog. to discover some secrets  

at first, the scientists cut one of the frog's legs off, then they told the frog to walk. The frog got up and walked, so  they learned that a frog could walk with just three legs. 

For the second experiment, they cut off a second leg from the frog, then they told the frog once more to walk. The frog was still able to walk with only two legs. 

but in  the third experiment, they cut off yet another leg from the frog and once more they told the frog to walk. However, the frog wasn't able to walk with only one leg. 

As a result of these three experiments, the scientists wrote in their final report that the frog had lost it's hearing after having three legs cut off