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

I have a big mouth and I am also quite loud! I am NOT a gossip but I do get involved with everyone's dirty business.

You can find some missing letters in the picture. By placing two particular letters in the spaces, you can form a nine lettered word beginning from one of the corners and going clockwise direction to the middle. Can you find out the letters and the word?

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?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

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?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

How can you write nineteen in a manner that if we take out one, it becomes twenty?