What Am I Riddles

Question:

Look at my apple, keep me near.

Listen closely, I'll put worms in your ear.

What am I?

Question:

The dirtier I am, the whiter I get,
Leave a mark on me when you stand, I'll leave a mark on you when you sit.

What am I?

Question: Each morning I appear to lie at your feet. All day I will follow no matter how fast you run. Yet I nearly perish in the midday sun. What am I?

Question: There are two sisters: one gives birth to the other and she, in turn, gives birth to the first. Who are the two sisters?

Question: You throw away the outside, eat the inside, and throw away the inside.