Final Answer:
The embryological development of different species revealing similarities in the early stages points towards common ancestry. Option A is answer.
Step-by-step explanation:
Embryological development provides insights into the evolutionary relationships among species. Similarities in early developmental stages suggest a shared ancestry, indicating that different organisms have common genetic pathways during embryogenesis. This is particularly evident in the study of homologous structures, where embryos of diverse species exhibit comparable features before divergence into distinct adult forms. Common ancestry, represented by shared developmental processes, supports the idea of evolution and a unified biological heritage.
Understanding embryological similarities has been a key factor in the development of the theory of evolution proposed by Charles Darwin. It signifies that despite the diversity observed in fully formed anatomies, a common genetic heritage unites living organisms. Therefore, option A, "Common ancestry," is the most fitting explanation for how embryological development reveals similarities among species.