In humans, two traits, rolling the tongue and the ability to taste PTC, depend on separate dominant genes located on different chromosomes. A man that can roll the tongue (assume he is homozygous) that cannot taste PTC married a woman that can not roll the tongue that can taste PTC (whose mother can not taste this chemical). What is the probability that their first child will: (write down the cross and your calculations)

a. Either not being able to roll the tongue or not being able to taste PTC?

b. Being both able to roll the tongue and able to taste PTC?

c. Being both able to roll the tongue and not able to taste PTC?

d. Either not being able to roll the tongue or being able to taste PTC?