A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?

This information is not sufficient. For considering a trait as dominant or recessive, we need data of at least three generations. This data is about only two generations. However, since both children and their parents have light eye colour, the possibility is that light eye colour is a recessive trait. Unless we know the nature of these two variants of traits we cannot tell which is dominant and recessive.

Mendel’s three laws of inheritance

Law of Independent Assortment

The law of independent assortment says that genes for different traits segregate independently of each other.

Law of Dominance

The law of dominance says that there are dominant and recessive traits. Dominant traits are defined as whichever phenotype is expressed in an organism that is heterozygous for the trait.

Law of Segregation

The law of segregation says that everyone has two versions (called alleles) for each trait—one from each parent—and that these alleles segregate randomly (see independent assortment) during meiosis.

Further references

1. What Are The Three Laws Of Mendel?
2. Principles Of Genetics
3. List Two Differences Between Acquired Traits And Inherited Traits By Giving An Example Of Each