Question

short pea plant tall pea plant f₁ all tall pea plants f₂ 3 tall : 1 short

Explanation:

Step1: Assign parental genotypes

Short pea plant: $tt$, Tall pea plant: $TT$

Step2: Determine F₁ genotypes

Gametes: $t$ (from short) and $T$ (from tall). All F₁: $Tt$

Step3: Determine F₂ gametes

Each F₁ ($Tt$) produces $T$ and $t$ gametes.

Step4: Calculate F₂ offspring genotypes

Cross $Tt \times Tt$:
Offspring genotypes: $TT$, $Tt$, $Tt$, $tt$
Phenotypes: 3 tall ($TT$, $Tt$, $Tt$), 1 short ($tt$)

Answer:

Parental (top) boxes: Left: $tt$, Right: $TT$
F₁ (bottom left) boxes: $Tt$, $Tt$
F₁ (bottom right) boxes: $Tt$, $Tt$