Вставить вот эти глаголы в пропуски:should, have to,can,might,May.​

There is an opinion according to which the ancestor of man was rather a scavenger, since he could not spontaneously occupy a higher ecological niche. and all the known tools of labor served to cut the remains of animals that were selected from predators. however, the question of when and why a person began to hunt still causes debate. in any case, thanks to hunting and meat food, the ancient man had a large supply of energy, which allowed him to bear cold better. the skins of dead animals were used as clothes, shoes and walls of the dwelling, which increased the chances of survival in a harsh climate.rowing appeared millions of years ago, and his role was much more important than in the life of a modern office worker. having freed his hands, a person could engage in intensive construction of a dwelling, the production of clothing, the processing of tools, the extraction and preservation of fire. the upright ancestors of people could move freely in an open country, where their life no longer depended on the harvesting of tropical fruits. already millions of years ago, they were free to travel long distances and get food in river drains. rowing played an insidious role and yet it was rather an advantage: the man himself came to the cold regions and adapted to life in them, but at the same time could find artificial and natural shelters from the glacier.