Life Science Practice Exam 2026 – Complete Preparation Resource

Alleles are the different forms a gene can take at a specific location on a chromosome. These variants arise because the gene’s sequence can differ among individuals, leading to different versions of the trait. An organism typically carries two alleles for each gene—one inherited from each parent—which can be the same or different. This explains why we observe variation in traits among individuals. A gene is the basic unit of heredity, a trait is the observable characteristic, and inheritance is the passing of genes to offspring; these describe broader ideas, while alleles specifically refer to the gene’s variants.