Describes a plant or animal that has been changed by scientists. genetically modified A type of medicine that prevents people from getting a disease. a vaccine All the animals and plants living in an area. an ecosystem An increase in the world's temperature caused by gases like CO2. global warming The natural home of an animal or plant. a habitat When all the individuals of a species have died (like dinosaurs and the dodo). extinct Someone who is used in a test for something such as a new medicine or product. a guinea pig The way the world's weather is changing. climate change