Clean riddles

The front of me is the source of a song Or to kiss with a fervor of love lifelong. My back is a plant fit for a queen, Crafted by needle, chemical, or machine.

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

I have four legs. I live in Africa. I am big and grey. I live in the river. What am I?

You can easily touch me, but not see me. You can throw me out, but not away. What am I?

I have more than 80 keys, but I cannot open any lock. What Am I?

I know a country. If you remove the last aplhabet of its name, it will become a part of your body. Do you?

A horse travels a certain distance each day. Strangely enough, two of its legs travel 30 miles each day and the other two legs travel nearly 31 miles. It would seem that two of the horse's legs must be one mile ahead of the other two legs, but of course this can't be true. Since the horse is normal, how is this situation possible?

Pronounced as one letter, And written with three, Two letters there are, And two only in me. I’m double, I’m single, I’m black blue and gray, I’m read from both ends, And the same either way.

I have foot, but there are no legs! What Am I?