Short medium what am I riddles

I take what you receive and surrender it all by waving my flag. What am I?

I have three eyes but only one leg. I still close one even if you beg. What am I?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

I can run, but not walk. Thought is not far behind me. What am I?

Physicists have built devices to move me very fast. My last seven letters can be commonly found in newspapers, magazines and journals. What am I?

I have keys but no locks. I have a space but no room. You can enter, but can't go outside. What am I?

I have lot of memories, but I own nothing. What am I?

What has one head, one foot and four legs?

Everyone has me but nobody can lose me. What am I?

I am alive without breath and cold as death. I am never thirsty but always drinking. What am I?