What does it mean when you see a full developed fruit on a plant

When you see developed fruit on a plant, you can safely
assume that the plant is in the process of completing its reproductive cycle. Fruits
develop from the ovary tissues of the plant, and are used for protection and dispersal
of the plant's seeds, which contain the baby plants to begin the next
generation.

Therefore, if you see a fruit, you know that at
some time in the past, there was a flower on that location in the plant. You also know
that the flower had an ovary, the female part. (It may have had both male and female
parts, as many plants do.)  You can also be sure that the female part of the flower was
pollinated, which means that pollen, which contains plant sperm, reached the stigma,
which is a receptor organ found on the female part of the plant. The sperm reached the
eggs, which grew into a seeds. You can tell how many eggs were fertilized by counting
the seeds inside the fruit.