Because you cannot test it or observe it.
A scientific theory are created through the scientific method, in the scientific method you need to be able observe it and experiment.
I am pretty much sure that C. Lyases is the answer.
Let me give some information about this.
Lyases are the main groups which show peculiarity in having more than several categorised groups having more enzymes than the other four.
Hydrolase does not fit this bill instead they contain less categorised groups.
Other two groups are not even having that much groups.
Hope helps ...
Well, the range is more limited. Let's say if you tried listening to Denver radio all the way in Texas, you wouldn't be able to listen to it.
Another one is that other electromagnetic waves with similar frequencies can interfere with each other
