Question: It is able, but not capable.
It can stop, but not go.
It is dead, but not yet perished.
It's a ghost, but not paranormal.
Is it high, or is it low?
Answer: It is high. All of the words that it is have the first two letters consecutive in the alphabet: ab, st, de, gh, and hi.
Question: My thickness is no more than a few centimeters, yet my depth can span to infinity. Although mundane, I intimidate most animals. When in my presence, you will inevitably follow me. What am I?
Answer: I'm a mirror.