Question 2
In the Punnett square for Tt × Tt, what is the ratio of the pairs of factors in the offspring?
The right answer is the one marked above.
1 TT : 2 Tt : 1 tt. Of the four boxes, one is TT, one is tt, and two are Tt — because Tt can be made in two ways and the other two in only one each.
Counted by appearance the same four boxes give 3 : 1, because TT and Tt plants are both tall and cannot be told apart by looking.