Answer: The correct answer for the blank is- 1. The number of genes that control the trait.
Phenotype represents the morphological form or physical characteristic of an individual. It is depicted by the genes ( segment of DNA corresponding to particular proteins, which is responsible for the trait of an individual).
This means that the number of phenotypes produced for a given trait depends upon the the number of genes that control the trait.
For exampe- Polygenic traits are controlled by more than one gene and they produce multiple phenotypes.
These traits depict wide range of variation in them ( such as human traits like height, color of skin).
