Answer:
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 I'm best when I am toast.
The homes of tiny creatures that collect in corners if you aren't vigilant about dusting.
What goes in the water black and comes out red?
A stellar five-Βlimbed sea creature.
What kind of fish chases a mouse?
The more of me you take, the more I appear behind you. What am I?