When plants with red flowers are crossed with plants with blue flowers, sometimes only red flowers are produced; other times either red or blue flowers are produced. Which gene is dominant?

The colors you see in flowers come from the DNA of a plant. Genes in a plant's DNA direct cells to produce pigments of various colors. When a flower is red, for instance, it means that the cells in the petals have produced a pigment that absorbs all colors of light but red.

Explanation:

Dominant refers to the relationship between two versions of a gene. Individuals receive two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, one allele will be expressed; it is the dominant gene. The effect of the other allele, called recessive, is masked.