Which of the following is NOT an example of a continuous trait?

Inherited traits that can be divided into a range of discrete values are called:

Genetic variation within a species is contributed by different factors. Which of the following genetic variation sources is attributed to changes in the sequences of the genes in the DNA?

A polygenic trait is controlled by two gene pairs. In a cross between AaBb and AaBb, what proportion of the offspring would you expect to have two additive alleles?

Skin color in humans shows a lot of variation. This is an example of which type of inheritance?

Which of the following types of inheritance is typically responsible for traits that exhibit continuous phenotypic variation? 

How many polygenes generally contribute to a quantitative trait?