Additional detail found elsewhere: (T = Tall and t = short)
Answer:
All are expected to be tall
Step-by-step explanation:
We are told that the T allele produces the tall trait, and the t allele produces the short trait.
Because the tall allele is denoted by an uppercase letter, it means it is the dominant allele, meaning if it is present even in one copy, the trait will be expressed. This is in contrast to the recessive short allele, 2 copies are needed for the trait to be expressed.
Individuals have 2 copies of every gene. Offspring that are TT, Tt, TT, and Tt all have at least one copy of the T (tall allele). Because this is the dominant allele, that means all of these offspring would be expected to be tall.