Cosy Pyro 4-Pack Women's Cotton Crop T-Shirts Short Sleeve Solid Cropped Athletic Top Round Neck Casual Workout Yoga Tees

Are these crop t-shirt made of cotton or polyester?

Do you sell your shirts in singles? I bought a set and would love to purchase more colors, however, I don't want duplicates of colors I already own.

Do the shirts srink during wash?

Would this look okay if worn under a dress with thin straps?