When a cross is made between a tall plant with yellow seeds $(TtYy)$ and a tall plant with green seeds $(Ttyy)$,what proportions of phenotypes in the offspring could be expected to be:
$(a)$ Tall and green.
$(b)$ Dwarf and green.

(N/A) To determine the phenotypic ratio,we perform a Punnett square cross between the parents $TtYy$ and $Ttyy$.
$1$. Gametes produced by $TtYy$: $TY, Ty, tY, ty$.
$2$. Gametes produced by $Ttyy$: $Ty, ty$.
By crossing these gametes in a Punnett square:
| | $Ty$ | $ty$ |
|---|---|---|
| $TY$ | $TtYy$ (Tall,Yellow) | $TtYy$ (Tall,Yellow) |
| $Ty$ | $TTyy$ (Tall,Green) | $Ttyy$ (Tall,Green) |
| $tY$ | $TtYy$ (Tall,Yellow) | $ttYy$ (Dwarf,Yellow) |
| $ty$ | $Ttyy$ (Tall,Green) | $ttyy$ (Dwarf,Green) |
From the resulting $8$ offspring:
$(a)$ Tall and green plants: $3$ $(TTyy, Ttyy, Ttyy)$. Proportion = $3/8$.
$(b)$ Dwarf and green plants: $1$ $(ttyy)$. Proportion = $1/8$.