For five decades the United Nations has diligently tried to prevent world wars and smaller wars. They have done a reasonably good job of it too considering how many nations are part of the United Nations. You mix that many people in a room from so many different cultures and it is a miracle they manage to keep peace.
mixing of the gene pool and thus encourages homogeneity and prevents heterogeneity
international treaty prevents it
An organization that Republicans like against their own self-interests because it prevents poor people from getting adequate care.
Alpecin is a hair product that prevents hair loss and promotes hair growth. It is a product that is sold internationally which is why the company is Alpecin International.
No, all micronations are allowed to stamp passports, nothing in international law prevents it.
The powers of government are divided to prevent any one branch from becoming too powerful. This prevents the United States government from becoming a dictatorship.
No, Antarctica has always been "public property". Anyone may explore it. Though International laws prevents you from taking it over.
Yes, you can remove flowers that are old from petunias, but do it by nipping them off with your fingers rather than pulling which can break off a large section. Removing old flowers prevents the plants from sprawling too much and encourages further blooming.
The nutrient that prevents beriberi
He prevents Tybalt from starting a fight which would bring everyone down. Also he doesn't make a fuss about Romeo even though he is a gate-crasher. He is welcoming to everyone who comes and encourages the young people to dance and have a good time.
Antarctica is protected under an international agreement that prevents anyone from governing taking over claiming, or owning property on it. I don't know of anywhere else.
Adequate water intake prevents leaves from drooping.