They are Transient, Imperfect and Ownerless. Everything that we perceive is like this. When eyes, ears, nose, tongue, body and mind receive sensations, we know them, just like knowing the monkey. Then we can be at peace. When sensations arise, know them.
Sensations are uncertain.
They exist dependent on change. And all of us here exist dependent on change. The breath goes out then it must come in. It must have this change. There must be both the in breath and the out breath.