Which of the following processes generates a continuum (spectrum) of varying phenotypes?
a) Incomplete dominance
b) Polygenic inheritance
c) Multiple alleles
d) Single-gene traits

option B: Polygenic inheritance

Explanation:

Polygenic inheritance in genetics and plant breeding can be defined as a type of inheritance whereby  one or a single trait or  characteristics(color)  is controlled by multiple genes (two or more genes). it is a continuous variation that depicts a normal distribution curve

the phenotype of a plant or an animal increases if when there is an increase in the number of genes controlling a particular trait or characteristics. polygenic inheritance are non-Mendelian form of inheritance in  nature and a  single trait expressed is as a result of the interaction of many or multiple genes that are quantitative genes in nature. examples are weight, skin color, height, e.t.c

i think the answer would be d