Answer:
Both old people and owls are said to be possessing this trait
My first is twice in apple but not once in tart. My second is in liver but not in heart. My third is in giant and also in ghost. Whole Iām best when I am roast.
Lighter than what I am made of, More of me is hidden Than is seen.
What has three ways out and just one way in?
What is full of holes but still holds water
What is so fragile that saying its name breaks it?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?