What has one letter and starts with an E?

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

1 rabbit saw 9 elephants while going to the river. Every elephant saw 3 monkeys going toward the river. Each monkey had 1 parrot in each hand. How many animals are going towards the river?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

What has many keys but can’t open a single lock?

How many sides does a circle have?

If a wheel has 54 spokes, how many spaces are there between the spokes?

What jumps when it walks and sits when it stands?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?