"Let them praise the name of the LORD, for he commanded and they were created."
There is no other justification needed other than this to praise God: that you even live and breath, you who were once dirt and water (carbon, hydrogen, and oxygen) and now is able to feel, and think, and dance. If you saw a statue come to life you would be amazed, and yet how can you find the birth of a child anything less than a miracle? Where there was no life, now there is.
Try as they might, no biologist can ever figure out what makes a man alive, what animates his cells and causes them to divide and grow. At any given moment there are billions of different processes occurring inside your body simultaneously, all of which work together and the resulting harmony is called "life".
Miraculously, it is this life which keeps every function running in oder to sustain and produce more life which sustains every function... and so on ad infinitum. It is this breath of life which overflows from God onto his creation and so all things great and small praise God for without Him we would have no voices at all. As easily as God has breathed life into a man so too can he take it away.
So let everything that has Breath praise the Lord for this is the reason it was given!