ok, you have here a normal kid asking normal questions. This is good as there are lots of us in the same boat. My just 2 yo comes out with some of these, tbh. The questions ARE incessant-I have 2 of them doing it! Its fabulous and bloody tiring.
What I am working towards doing with my older child, who is nearly 4 , is showing him how we find out the answers to these questions.
Now obviously there are different ways of doing this. You can show her how to google to an extent-ok prob not the reading, but she can look out for pictures. You can show her how to look up info in books, in your home or in the library. If they are sciencey questions then consider getting her to doing easy experiments, gardening, or just playing in water etc and talking to her about the effects.
Also I'd say that why do flowers bloom and why does the sky stay up are a. typical toddler questions and b. not very specific. Work with her to find out exactly what she wants to know and explain to her why its helpful for you to know this. Is she saying "what is the point of flowers?" or "how do flowers form"? Or does she just want a general discussion about flowers, as in, look mummy I've seen a pretty flower.
If you are interested in skill building, and want her to be bright and sucessful in the future, then the ability to work out exactly what her question IS and be as independent as possible in finding the answer, will be much more useful than any specific knowlege.