1 The question asks for a certain quantity of examples in a list (Name 6 factors that contributed to the start of World War I, What 3 subatomic particles constitute an atom? etc).
2 The question is academically precise and, therefore, indecisive in the wording (What are the 2 kinds of loading most professional engineers and academics in the field of engineering today generally consider to be relevant in most cases when considering typical types of structure usually made of common materials using well-understand methods?)
3 The question challenges the answerer to defend a position as opposed to merely rattling off a list based on knowledge alone, thereby invoking higher levels of Bloom's Taxonomy. (What are 4 arguments that could be used to defend arguments made by the physicists of the day that electromagnetic waves must move through an illusive substance called 'the ether?)