In non-Mendelian genetics, what is the term for a trait controlled by multiple genes?

Which non-Mendelian inheritance pattern involves the presence of more than two alleles for a particular gene?

Which of the following is true regarding the inheritance of polygenic traits?

In a certain species of birds, the allele for long tail feathers (L) is incompletely dominant over the allele for short tail feathers (l). If a homozygous long-tailed bird (LL) is crossed with a heterozygous bird (Ll), what will be the phenotype of the offspring?

In a certain species of flowers, the allele for blue petals (B) is incompletely dominant over the allele for yellow petals (b). If a homozygous blue flower (BB) is crossed with a homozygous yellow flower (bb), what will be the phenotype of the offspring?

In a certain species of plants, the allele for smooth leaves (S) is incompletely dominant over the allele for prickly leaves (s). If a homozygous smooth plant (SS) is crossed with a heterozygous plant (Ss), what will be the phenotype of the offspring?

In a certain species of fish, the allele for red fins (R) is incompletely dominant over the allele for blue fins (r). If a heterozygous fish (Rr) is crossed with a homozygous red-finned fish (RR), what will be the phenotype of the offspring?