I live in the sea but I’m small, not tall, With a bend in my body, I’m curled like a ball. Red when I’m done, in water I swim, What am I?

I have a shell, but I do not have a tail. I am often seen in supermarket refrigerators and breakfast menus.

I hold water, high up in the sky but when I fall it can hurt or you could even die. I can nourish, but to get me, it's not so easy to try.

I'm Mario's way of getting around, or a way to move oil from out of the ground. You may use me to program, you use me to sing. What am I, so useful for many a thing?

My whispers travel where voices can’t reach. Obscure yet precise, I have secrets to teach. Repeated in patterns, though silent to most. Shapes and sounds, but invisible like a ghost. Everyone here can see my name, yet I remain hidden.