What has one letter and starts with an E?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

Why 1729 is a magic number? Answer Logically.

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

During which month do people sleep the least?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

How many times can you subtract the number 5 from 25?