Which of the following statements about alleles is true?

Alleles are variations of a gene that occupy the same position on homologous chromosomes. Each individual has two alleles for each gene, one inherited from each parent. These alleles can be either dominant or recessive. When an individual has two different alleles for a trait, the dominant allele will typically mask the expression of the recessive allele. This means that the traits determined by the dominant allele are expressed in the phenotype, while those determined by the recessive allele may not be expressed unless the individual has two copies of that recessive allele.

Understanding that alleles can come in dominant and recessive forms is crucial in genetics, as it helps explain how traits are inherited and expressed in offspring.