A lot, like Windmills, Clogs, Cheese, Tulips and apple cake xD
tulips (two lips...)
If you mean "Holland tulips", it means tulips from Holland.
There are no specific collective noun for tulips. I have seen suggested, an explosion of tulips and a tiptoe of tulips. However, any noun suitable for the situation can be used, for example, a field of tulips, a bouquet of tulips, a bunch of tulips, etc.
If you are saying that "1 in 4" of the tulips are red, the answer would be 4 of the tulips are red.
No, tulips are multicellular organisms.
Tulips are angiosperms.
Tulips
Nobody else makes Amstel beer, gouda cheese or tulips.
Tulips are bulbs
Tulips are a spring bulb.
Tulips Tulips