It's Riddle Time!

I wear a cap but never need a bottle opener. What am I?
Answer: Pen

I grow shorter as I age, though I never celebrate a birthday. What am I?
Answer: Pencil

I'm known for keeping things together without a drop of glue. What am I?
Answer: Stapler

You can erase with me, yet I'm not known as an eraser. What am I?
Answer: Pencil with an eraser

I have many teeth, but I don't bite or chew. What am I?
Answer: Comb

I leave a mark when I talk, but I never make a sound. What am I?
Answer: Highlighter

I'm full of holes but still hold water. What am I?
Answer: Sponge