If one parameter of drakes equation is 0, then the whole equation is 0, because it is just a series of multiplications. And we know for sure it cannot be 0, sin

If one parameter of drakes equation is 0, then the whole equation is 0, because it is just a series of multiplications. And we know for sure it cannot be 0, since we live, and we can theoretically be detected by the electromagnetic waves we emit -- and far less likeley by artifacts such as the voyager 2 probe. So the likelyhood of a planet, capable of supporting life is not 0, but at least 1*10^-11 (100 billion stars exist in our galaxy, and at least one [the sun] has a habitable planet [the earth]). That said, this particular parameter will likeley be higher, since we have found several exoplanets, that are estimated to be habitable.