Which of the following is an example of an informal definition?
1.Aquaculture is the science and practice of growing fish for food; in other words, aquaculture is fish farming.
2.Aquaculture has become an important part of the world's food supply. Fish that are farmed using aquaculture are often used for commercial purposes. Researchers are working to expand aquaculture to take a role in marine and freshwater restoration projects.
3.Like so many modern innovations, aquaculture solves certain problems while it creates a few new ones. Opponents of aquaculture claim that farmed fish can transfer diseases and parasites to wild fish populations if the two environments mix.
4.The Food and Agriculture Organization of the United Nations defines aquaculture (noun) as "the farming of aquatic organisms: fish, mollusks, crustaceans, aquatic plants, crocodiles, alligators, turtles, and amphibians."