You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

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

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

I am the beginning of the end, and the end of time and space. I am essential to creation, and I surround every place. What am I?

What has to be broken before you can use it?

Can you name three consecutive days without using the words Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, or Sunday?

I have no life, but I can die. What am I?

How many letters are in the alphabet?