Answer: d. currently a source of much controversy
Step-by-step explanation:
Genetically modified food are the food products in which the genetic make up of the foods are altered or modified by inserting the genes of animal or plant genes or the entire DNA. This process helps in improving the quality and quantity of foods.
These foods are the source of much controversy due to the ethical and health issues associated with them. Ethical issues suggests that that how the manipulation of one organism genome into another can destroy the integrity of the food producing species. Also some humans are vegetarian, the addition of the animal genes can make their food non-vegetarian. Health issues may occur if the food produce allergy or disease to the consumer.