We think of fruits as being sweet. When we eat fruits, we are eating the fleshy part of the plant that protects the seeds. This means that the seeds are contained within the plant. Some examples are apples, peaches, pears, and oranges. Some fruits are seedless meaning that the do not produce seeds. Some examples of seedless fruits are watermelon and grapes.
We do not think of vegetables as being sweet. When we eat vegetables, we are eating the stalks, flowers, leaves, and roots of the plant. Some examples of vegetables are broccoli, cauliflower, spinach, carrots, and onions. We eat the stalks and flowers of broccoli and cauliflower. We eat the leaves of spinach. We eat the roots of carrots and onions.
Many foods that we call vegetables are really fruits. These include tomatoes, squash, and bell peppers.