Homogenous means to be alike so in this case it is stating that the group of was similar and had little variation majority of dogs are Staffordshire bullterries

the image of the dog on is a great example of how expressive dogs upper facial area can be. I also noticed breeds like French Bulldogs seem to have a lot of expression I find this interesting since this breed of dog is completely selective breeding done by man kind since this breed cannot give live birth on its own and must have a C-section in order to give birth and have there offspring survive.

pedagogical is an adjective relating to the methods and theory of teaching. https://dictionary.cambridge.org/dictionary/english/pedagogical a fancy way of saying Ostensive cues such as eyebrow movements are relevant to learning interaction between dog and humans.