Multiple choice What will be the genotype(s) of F1 upon crossing 'TtRr' with 'ttrr'? TtRr TtRr and ttrr TtRr,Ttrr, ttRr, ttrr TTRR, ttRR, TTrr and ttrr Reveal answer Fill a bubble to check yourself C Correct answer Explanation A cross 'TtRr' with 'ttrr' is test cross and produces TtRr, Ttrr, ttRr, ttrr genotypes in F1.