For the last question it's either C or D.
Answer:
The test cross is shown below
T T
t Tt Tt
t Tt Tt
The alleles shown in the vertical side (tt) are recessive and come from the male parent. The alleles TT are dominant and come from the female parent.
For the variety of offsprings to be 100% tall, the recessive parent had to be crossed with a homozygous dominant parent. If the female was heterozygous with which the cross was done,then there would be small tomato plants in the offspring generation.
Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as true-breeding. In this process the parents will pass down specific phenotypic trait of their offspring. True bred organisms will have pure genotype (genetic make up of an organism) and will therefore produce certain phenotype.
