Question

When Mendel crossed a Tall plant with a Dwarf plant, the ratio of dwarf plants in F2 generation was ___ %.

Answer 1

When Mendel crossed a tall plant (with n' traits on DNA) with a dwarf plant (with U traits on DNA ), the F1 generation was found to be tall.
There were no dwarf or medium height plants in F1 generation. This means that only one of the parental characters was seen.
But when F1 generation plants were self-fertilized, it was found that some plants were dwarf (25%) some were tall (75%) in F2 generation.