The tomato is a red fruit. It is shiny and smooth, and has many small seeds. The tomato is green when it is unripe. It is very sour and it is good for you. It slowly changes color from green to red as it gets more ripe. There are many different types of tomatoes. Most tomatoes are red, but some special kinds are yellow or orange when they are ripe. Tomatoes are used a lot in Italian food. They are also used to make ketchup. Sometimes, people mistake tomatoes for vegetables, but they aren't, because they contain seeds.