Well tomatoes actually grow off a tomato tree, not the ground. This is because tomatoes and apples are both fruits – they are a result of a plant flowers being fertilised and making seeds so that the tree can reproduce.
Vegetables are different because they’re a bit of a plant that isn’t the leaf that we like to eat and don’t contain seeds. Potatoes and carrots come from the ground because the plant puts lots of stored energy underground where herbivores can’t see them (but we can because we’re clever) and these are called root vegetables – because they’re from the root of the vegetable. Celery is from a plant stalk, just like rhubarb.
Herbs are the leaves of plants, like coriander, basil and thyme.