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WAEC Biology 2022 Question 45

Question 45

Mendelian Inheritance

Two tall plants were crossed and all the F1 plants were tall. When the F1 plants were selfed, some of the F2 plants were tall while others were short. What are the possible genotypes of the original plants?

  1. A.Tt and tt
  2. B.TT and TT
  3. C.tt and tt
  4. D.TT and Tt
Show the answer and explanation

Answer: D (TT and Tt)

Explanation

Both parents are tall and all F1 are tall, so at least one parent is TT; short F2 plants mean some F1 were Tt, so the other parent carried t: TT × Tt.