The riddle likely refers to "thoughts" or "ideas." They can be conceptualized or understood (seen) but are intangible and cannot be physically observed (not seen). They can be expressed verbally or mentally (heard) but lack a physical sound on their own (not heard). Thoughts exist in the mind, giving them a sense of being alive, yet they don't have a physical form that can die.
Kids are both to be seen and heard
No, unfortunately at the end Episode IV Ruben dies and is not seen again in the series.
Music or sound is something that can be heard but not seen.
Ukitake is currently alive.
Can a son make you sell the house after his father dies and the mother is still alive?
She is heard but never seen: Heard in (How to Spank A Star; season 3)
Water is possibly the only thing that can not be caught but can be seen and heard.
It's seen & NOT heard- It means they should not interfere in adult conversation.
It isn't ! A flash of lightening is seen BEFORE a peal of thunder is heard.
The cast of Seen and Not Heard - 2009 includes: Kyle Merryman
shia's character dies but come alive after fox said she loved him
A lotus flower. A lotus must die in the ground to become a flower again. So it will live when it dies. Even if the flower is alive, it must die in order for a seed to be produced. Therefore, it must die to live. The thing that lives when it's dead, and dead when it's alive is.. lotus.