What essential criteria must be met in order to execute a successful mapping cross? check all the statements that apply. a. the genotypes of the offspring must be readily determined from their phenotypes. b. one parent should be homozygous dominant and the other homozygous recessive for all the genes being mapped. c. one parent should be heterozygous and the other homozygous recessive for all the genes being mapped. d. recombination must occur in the sex that displays genetic heterogeneity.