How Related Are They Really?

When my cousin was in the zoo he liked monkeys of all kind,
So then he went to see the ape and his little brother went to see their smallest monkey the marmoset,as you know monkeys are our primates,
So then my cousin's little brother put his hand up against the glass and the marmoset saw him and so it came over and put it's hand up against the glass, and guess what the marmoset had done with their hands still lined up?the small little creature
Had shed a tear because they are so closely related to us,so why not help them,and stop killing for no reason?