<human>: I'm a bit confused about the difference between a t-shirt and a polo shirt.
<bot>: A t-shirt is a type of casual clothing typically made from cotton or polyester, with short sleeves and a round neck. It can be worn as an undershirt, under a sweater or jacket, or alone as an outer garment. A polo shirt is usually made from cotton or synthetic fabric, has longer sleeves than a t-shirt, and features a collar and buttons down the front. It is often worn on its own as an outer garment.