Difference between sealed and shut

[Stone]

English Language Tests, Intermediate level

ESL/EFL Test #42 "Keeping it Quiet", question 4

If you want me to say nothing about it, I promise that if anybody asks then my lips are ..........

(a) stuck
(b) closed
(c) shut
(d) sealed

English Language Tests, Intermediate level

ESL/EFL Test #42 "Keeping it Quiet", answer 4

If you want me to say nothing about it, I promise that if anybody asks then my lips are sealed.

Correct answer: (d) sealed

Your answer was: incorrect
If you want me to say nothing about it, I promise that if anybody asks then my lips are stuck.
_________________________

Would you please explain the difference between "sealed" and "shut"

Thanks a lot in advance

Stone

[Conchita]