1. Why does the egg in salt water float?
2. Why does the egg float in salt water?
[Are both the same in meaning?]
3. Compare the two buildings. Which one is the taller of the two?
4. Compare Building A with Building B. Which one is the taller between the two buildings?
5. Compare Building A and Building B. Which one is taller, Bilding A or Building B?
[Are they all grammatical?]
1 and 2 mean about the same, but 2 is phrased more smoothly, with the prep phrase AFTER the verb it’s modifying.
The others are all grammatically correct, but be sure to correct the spelling error in 5.