Then please tell the group what the question should be? - the question should have been 'why and how are certain behaviours (e.g. puppies' reaction to pus) inherited?'
I think it has already been answered, at least in part. Please read Island Man's post on your 'why are smells passed on in DNA' thread. He explains clearly why some behaviours give reproductive advantages and so are retained within populations, with genes being the basic unit of inheritance.
You probably need to read up on the basics of genes, inheritance and evolution.
Some background reading of published scientific papers would do you no harm, too ...