Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

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

John is the son of Jacob.
So,
Jacob is the_____of John's father?

What type of tree can I carry in my hand?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

The first person saw the bridge step on it and crossed,
the second person saw the bridge did not step on it but crossed,
the third person did not see the bridge did not step on it but crossed.
Who are these people?

No matter how little or how much you use me, you change me every month. What am I?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

Why are televisions attracted to people?

The centre of the third figure is empty. What digit should fit inside?