Question

Which cross will yield four phenotypes in the 1:1:1:1 ratio?. .A] rryy x rryy. B] RrYy x rryy. C] RrYy x RrYy. D] RRYY x rryy

Answer 1

 It's (B). The Punnett square is a 4x1: 

_____RY_____Ry_____rY_____ry___ 
ry____?_______?_____?______?_____ 

If you fill it out, you'll see 4 different phenotypes... 

[(A) produces a 1:0 phenotypic ratio]