what is the difference between λαός and κόσμος and άνθρωποι ?
what is the difference between λαός and κόσμος and άνθρωποι ?
λαός nation
κόσμος world (also used as άνθρωποι )
ο κόσμος έχει τρελαθεί. (οι άνθρωποι)
άνθρωποι people
άνθρωπος is more like "human" (the species) αnd άτομο more like "person"
example with άτομα: 
-πόσα άτομα θα έρθουν στο πάρτυ? / how many people are coming to the party? 
ιt would be weird to use άνθρωποι here ("how many humans are coming to the party").
some examples with άνθρωπος/άνθρωποι:
-είναι καλός άνθρωπος / he is a good person (here άνθρωπος = person in english)
- οι άνθρωποι κάνουν κακό στο περιβάλλον. humans are hurting the environment (here the word άτομα would sound really weird)
άτομα the plural of άτομο means people also . you can use it the same way as ανθρωπος
ατομο- person, people -ανθρωποι