The idea of the soul is universal. People have always seen themselves apart from their body. They are certainly not reduced to brain functions and chemistry. The body is only a house for the man or woman on the inside, and this life is only a transitional, and a school where we learn in anticipation of the world to come.
Soul is the energy ,running in the body,which make all the organs of body alive ,Heart beat need the impulse to beat. Lungs need strength to breath. When this soul leave the body,it is dead. So every living thing has got a soul which make the alive and they can do their daily function.
This is a very difficult question to answer, because simply put, it is difficult to put into terms how the soul exists in each of us, but rather than it being a keen wish or a hope, there has been much study by many great thinkers and whilst difficult to verify empirically the conclusion is that souls do exist. The problem of consciousness is science is one of the biggest arguments in favour of us having an immaterial soul.
There is no individual soul, because there is only one life and each "living" thing is a manifestation of it. The concept of an individual soul was invented to make some people special, and to give the individual something they could lose if they transgressed the rules of the local religion club. This one life manifests as the motion of the stars, planets and the rest of the cosmos. It is manifest in the complexity of electro/bio/chemical processes through which our brains experience consciousness. For most people it is easier to imagine an ill defined "soul" as our motivating force, than to conceive of the incredible complexity that exists just in a single cell.
There's no way I can prove a negative. What I will say instead is that there's no reason to believe anything until there's some good evidence for it. There is absolutely no evidence that could even begin to suggest that something like a soul exists. So until such evidence can be produced, we're justified in disbelieving the claim.
Furthermore, we now know that minds are products of brains. All conscious thought is a product of electrochemical signals in the physical brain. Indeed, altering the physical brain (such as through some trauma) alters the conscious mind. If this is the case, then if we assume the soul to retain consciousness, then it is also a part of or product of the brain and does not survive death and so is irrelevant.