Tongue rolling

This task is about dominant and recessive genetic characteristics.
Read the information below about a genetic characteristic found in a family.
Pam and Greig had three children, all boys (Jason, Brian, and Ted). Pam and Greig could both roll their tongue, but of their children, only Jason and Brian could. Later, Jason married Anna (who cannot roll her tongue). They had a pair of identical twin girls called Cherie and Julie; both girls could roll their tongue. Ted later married Mary (who could not roll her tongue), and they had three children, Annie, Claire, and Pablo. None of their children could roll their tongues.

Question Change answer

a)  Use the information to complete the family tree below.
     Write the person's name under each symbol and shade the symbols where necessary.

Question

b)  Look at the chart above.
     Is the ability to tongue-roll a dominant or a recessive genetic characteristic? 

    • Dominant

    • Recessive

Explain your answer below.