How is a trait such as fur color is passed down from parents to offspring?

A trait is a characteristic, such as color or size, that is inherited by an offspring from its parents. The genes that control a trait come in pairs, one gene from each parent. We represent these gene pairs by writing a combination of two letters. For example, if one parent contributes a gene for blue eyes (c), and other parent contributes a gene for brown eyes(C), then we write the offspring’s eye color trait as Cc. This combination, of the two genes that determine the trait, is called a genotype. Hope this helped :)

The answer is constant.