A chain is never stronger than it’s weakest link. A puzzle is never completde until each piece is in their right place.
And so it is with everything in our world. Everything is connected and has it’s special place in the pattern.
Holism means that each piece is a part of something much more bigger and the system it is part of, do not work if any piece is missing.
Here is a short trailer from a movie you can rent at https://vimeo.com/ondemand/theconnecteduniverse and which explain holism in a good way.
If you do not take care of each part of yourself and see each piece of you as a part of something bigger, you will not be able to be fullfilled and to accomplish what you are meant for during this life of yours. But in the same time, you cannot be selfish but have to realize that you are part of something much bigger and you are coexisting with everything else in this world. You cannot separate body, mind and soul from each other and you cannot exist without coexisting with everything else around you.