Answer:
Tall and short trees are genotypically homozygous for their trait
Intermediated trees are genotypically heterozygous for their trait.
Step-by-step explanation:
Let the allele representing tall trait be "T"
and the allele representing short trait be "t"
It is given that when a tall and short plant is fused all the offspring are of intermediate height.
This simply means that the both the plants are genotypically heterozygous for their traits
Genotype for tall tree - TT
Genotype for short tree - tt
TT * tt
Tt, Tt, Tt, Tt
All the offspring are of intermediate height.
Now these two plants of intermediate height are crossed
Tt * Tt
TT, Tt, Tt, tt
Out of four plants two are of intermediate height, one is of tall heingth and the remainig one is of short height