1. "Genes" refer to genes, which are the fundamental units of heredity.
2. Genes are the plural form of "gene," and they determine the traits of all living organisms.
3. Variation among humans is constrained by the possible combinations of our genes.
4. Scientists are on the verge of being able to manipulate human genes to influence the aging process.
5. Natural selection ensures that only the most suitable individuals survive to pass on their genes to the next generation.
6. The stripes on the Semper Augustus were caused by genes associated with a virus.
