Life is so diversified that to any statement I could make about living organisms there are exceptions. Because of the many exceptions, I should qualify everything I say with hedging phrases such as 'generally,' 'usually,' and 'almost always' But I'm afraid the constant repetition of these hedges will slow me down and bore you. So let's make a pact now that I forego the hedging phrases, and you are to understand that almost all my statements may have rare exceptions.