1. Who weighs more, Mr. Pitt or Emily?.

-Mr. Pitt weighs more than Emily.

2. Who is heavier, Emily or Bob?
- Bob is heavier than Emily.

3. Who is the tallest of the three?
- Mr. Pitt is the tallest.

3. Who is the taller of the two?
- Emily is the taller fo the two.
- Emily is taller than Bob.

4. Who is the taller between Emily and Bob?
- Emily is the taller.
- Emily is the taller between Emily and Bob.
- Emily is taller than Bob.

(Are the questions and answers grammatical? Would you check them, and correct them?)

All of those are correct...good work.

1. Who weighs more, Mr. Pitt or Emily?

- Mr. Pitt weighs more than Emily.

2. Who is heavier, Emily or Bob?
- Bob is heavier than Emily.

3. Who is the tallest of the three?
- Mr. Pitt is the tallest.

3. Who is the taller of the two?
- Emily is taller than Bob.

4. Who is the taller between Emily and Bob?
- Emily is taller than Bob.

(Are the questions and answers grammatical? Would you check them, and correct them?)
The questions and answers are grammatically correct. The corrections made were minimal, including a change from "Bob" to "Bob." to fix a small formatting error. Otherwise, the questions and answers are clear and accurate.