Question

Suppose you cross a true-breeding blue flower with a true- breeding yellow flower and the next generation is all blue flowers what dose this outcome to tell us

Answer 1

It tells us that this is a pattern starting with a blue flower then a yellow flower then a blue flower and then a yellow flower and so. on...

Answer 2

The allele for blue flowers is “B” and the one for yellow flowers is “Y”.  

A true-breeding specimen must be homozygous, so the blue flowers must have the genotype “BB” and the yellow ones must be “YY”. If you cross a flower with genotype “BB” with one with genotype “YY”, all the offspring will be “BY”. If a “BY” flower appears blue, then the blue allele must be the dominant to the yellow allele.