Final answer:
GMOs are products of modern biotechnology methods that enable precise genetic modifications, often including genes from different species, while genetically altered foods from the past were typically created through artificial selection, which is a traditional breeding practice.
Step-by-step explanation:
Differences Between GMOs and Genetically Altered Foods of the Past
The key difference between GMOs and genetically altered foods of the past lies in the methods and precision used to alter the genetic makeup of organisms. Genetically modified organisms are produced by directly manipulating their DNA through modern biotechnology techniques, which can include inserting, deleting, or modifying specific genes. This contrasts with traditional methods such as selective breeding or artificial selection, which have been used for thousands of years to cultivate desired traits in plants and animals. While both methods result in genetic changes, GMOs enable the introduction of specific and precise modifications that were not possible with older breeding techniques.
Furthermore, GMOs can possess genes from different species — something that traditional breeding could not achieve. Modern GMOs often undergo rigorous safety assessments for potential human health and environmental impacts, which include evaluations for toxicity, allergic reactions, gene stability, and potential cross-breeding with non-GM plants. These assessments provide an additional layer of scrutiny compared to conventional foods.
Answering the student's question, option B is incorrect because the number of modifications isn't necessarily fewer in older methods; it's the specificity and technique that differ. Option C is inaccurate because GMOs are indeed intended for human consumption, while option D correctly indicates that genetically altered foods of the past were created through artificial selection, reflecting a blend of human selection and natural genetic variation without direct genetic engineering.