What word begins and ends with an E, but has only one letter?

I am white when I am dirty, and black when I am clean. What am I?

The more you take me, the more you leave me behind.
Who Am I?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

A man started to town with a fox, a goose, and a sack of corn. He came to a stream which he had to cross in a tiny boat. He could only take one across at a time. He could not leave the fox alone with the goose or the goose alone with the corn. How did he get them all safely over the stream?

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

What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.