'A Las Vegas-style wedding has no room for parents or misty-eyed aunts.'
'Room' is a simple word that we all know, eg. the dining room. It is a countable noun. However, in the example above, 'room' means 'the ability to accommodate the contents', eg. leg room. It is an uncountable noun.
Now decide in each case whether the word 'room' refers to definition A (as in dining room) or B (as in leg room):
1. There is no more room in my room for any more books.
2. When an ambulance sounds its siren, motor vehicles should make room for it to pass.
3. The living conditions in Hong Kong are generally very crowded. Not everyone has their own room.
4. Do you have any room for dessert?
1. B, A