Some people can roll the tongue into a tube shape, while others cannot. Practicing is not likely to help because tongue-rolling is an inherited trait. The allele for rolling the tongue (R) is dominant to the allele for not being able to roll the tongue (r). Look at the Punnett square. It shows a cross between two parents with at least one R allele. Drag each option to its spot to correctly finish the Punnett square.