Fruit is one of the food groups found on the food pyramid that must be consumed on a regular basis in order for a human to sustain good health. These fruits are created by plants specifically so that other animals can eat them, so many individuals consume fruit where they would not consume other organisms.
Flowers, fruits and seeds are all a part of the reproductive cycle of many plants. Plants with fruits usually have flowers that must become fertilized. Then, when these flowers are fertilized, the ovaries of the flowers turn into fruit. This fruit is usually edible.
The reason why these plants develop fruit is to get animals to consume the fruit and distribute the seeds by dropping them. This allows plants to spread their offspring into areas where they will not compete with the parent plants. Many seeds pass through the digestive system of the animal and end up in the animal's feces, where they have plenty of fertilization and can then drop to an area where they can grow.
Some fruits consist only of a ripened ovary and seeds. The ovary that is contained in the flower swells in size and the petals of the flower eventually fall off, exposing the fruit underneath. Berries are fleshy, though sometimes tough. Some fruit---called pepos---have thick outer edges that contain the fruit and seeds within them, such as with watermelons and pumpkins. Some fruit has compartments that are separated by leathery rinds, such as with oranges and other citrus fruit. Some fruits actually have a hard center with a seed on the outside like pecans and macadamias. The fruit can sometimes have an edible outer side while having a core that is usually not consumed, such as with apples and pears. Other fruits are dry instead of having juices in them, such as with legumes, turnips and Mexican jumping beans. Fruits can sometimes become very hard, such as with the case of nuts.
All of these fruits listed only includes those that consist of a single ripened ovary. Many fruits have multiple ovaries that cluster together, such as with blackberries and raspberries. Many flowers sometimes combine together to form fruits like pineapples.
Individuals who cannot identify a particular fruit can have that fruit sent to a horticultural society. These societies examine flowers, fruit and seeds to determine what kind of fruit are growing. This will help determine whether the particular fruit is safe for human consumption, or if the fruit might make a human consumer sick.