In the broadest sense of the term, we have modified the genes of almost everything. We used selective breeding to breed the most resistant form of crops, the largest sized chickens, and others. In recent years we have even modified them through gene splicing and other methods. Nearly everything we eat, including including "organic" foods have been changed from their original DNA structure, in fact we do not even know anything's original genetic structure because of this. Genetic modification could also include mutations. Some crops have mutated due to pollution, disease, or other effects such as climate change. Without genetic modification our world would differ from what it looks like today.
Oceanic crust has been forming on Earth for over 4 billion years, all of the sea floor older than <span>about 200 million years. </span>
