Why can we see? Why can we hear? Why can we talk? Why can we stand, walk, jump, and sit? In other words, how do we live in this world? Thanks to science and technology, we know now. We can see for the reason that we have a pair of eyes. We can hear for the reason that we have a pair of ears. Wecan speak for the reason that we have a mouth and vocal chords. We can stand and perform locomotive [...]