Answer:
Attached ear lobes are recessive to free ear lobes, so an individual must be homozygous recessive (ee) in order to have attached ear lobes. Therefore, we can conclude that since both of Lisa's parents have attached ear lobes, they are both homozygous recessive (ee). In a cross between two homozygous recessive parents, all offspring will be homozygous recessive, as shown in the Punnett Square below:
e e
e ee ee
e ee ee
Since Lisa must be homozygous recessive, she must have attached ear lobes.
