What are the three main beliefs of tibetan buddhism?

1. all humans are the same 2. All worlds have potential to create a god 3. non-violence 

Firstly, the promotion of human values such as compassion, forgiveness, tolerance, commitment and self-discipline. All human beings are the same in the sense that we all want happiness and do not want suffering.

Secondly,  the promotion of religious harmony and understanding amongst the worlds major traditions. Despite philosophical differences, all major world religions have the intent to create good human beings. 

Thirdly, to work to preserve Tibet's Buddhist culture, a culture of peace and non-violence :)

The correct answer is a. when they started making tools that will them in cultivating lands, they could raise crops and that made them attached to one place for a longer period of time. after that, they started domesticating animals and building their own permanent settlements that resemble the ones we have today.