What kinds of advantages, in terms of evolutionary fitness, do cooperative behaviors provide among different species of non human primates, and under what selective pressures would behaviors such as altruism (toward kin and nonkin) be likely to evolve

Throughout the overview segment elsewhere here, the benefits including its particular circumstance are listed.

Explanation:

Being willing to hunt with either a community relatively successfully, thereby increasing their likelihood of succeeding as well as physical inactivity.Selective pressures such as illness as well as predators will assist to evolve altruism because grooming allows the person to have been groomed first, but also protects diseases from being transmitted through lack of hygiene.Grooming encourages people to bond, which enables less friction and increases development by increasing security.  

To kill bacteria from our body especially from stomach