Final answer:
The structure of DNA is an example of a complex adaptation that implies Earth's age exceeds 6,000 years, aligning with the scientific understanding that Earth is approximately 4.6 billion years old.
Step-by-step explanation:
The question you've asked pertains to an example of a complex adaptation that indicates that Earth must be much older than 6,000 years. The correct answer is D) The structure of DNA. DNA is a fundamental molecule for life that carries the genetic information necessary for the reproduction, functioning, and growth of all living organisms. The complexity of the DNA structure and the vast amount of genetic information it contains suggest a long evolutionary history that far exceeds the 6,000-year timeline. This aligns with the scientific consensus that Earth is approximately 4.6 billion years old. Moreover, the gradual geological processes identified by scientists such as Charles Lyell and the theory of evolution proposed by Charles Darwin rely on a much older Earth to account for the slow and incremental changes that lead to the diverse forms of life we see today. Similarly, the whale flipper reflects convergent evolution, which further supports Darwin's theories.
Biogeography and the study of the fossil record, which show dinosaurs originated about 200 to 250 million years ago, also indicate a long-term biological evolution that requires an Earth much older than a few thousand years. These insights, coupled with the evidence of life's rapid emergence in the primordial ocean, underscore the complex adaptive systems that exist in nature, revealing a much more ancient and intricate world.