Scientists have genetically modified crops and animals in several ways:
1) Tomatoes have been engineered to produce proteins that transport salt into vacuoles, allowing the plants to thrive in salty soil.
2) Sheep have been cloned to produce Factor IX in their milk, providing an alternative way to obtain this blood-clotting protein needed by hemophiliacs.
3) Rice has been modified to produce beta-carotene, providing a new source of vitamin A to address deficiencies in developing nations.