What are the function of the UN

The main function of the United Nations is to preserve international peace and security. Chapter 6 of the Charter provides for the pacific settlement of disputes, through the intervention of the Security Council, by means such as negotiation, mediation, arbitration, and judicial decisions.

[I copied this from the internet, but hope it helps!]

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms