It is not true at all, that every body can do everything. There are hundreds of things around us, and we can see that in our societies, communities, neighbourhoods, and even in our own families (no offence intended!); certain number of people can do only certain things, and certain other people can do only certain other things. There are many common needs, that we all need to do, and can do; and we do these, since without carrying out these acts, we cannot survive. In fact, by the nature of things (based on our own bodies, minds, and intellects), every body does not have capability of doing everything; it is just our humble and nice wish.