Sheep-herder=is a person whose job is to take care of sheep to guide and make sure a group of people somewhere. Hence guardian / custodian shop. eg:-Sheep-herders should be guardians / custodians of the (---------).
... only 2.8 million people. Most of them(O) are herders. Most of they(X) are herders. 這裡的whom代替了...
... once every two weeks through the tourist season provides the herders with enough income to replace the animals lost to snow leopards. 在...