Why do oranges have sections in them?

Typical flowers have male and female parts. The male part bears the pollen and the female part is called the pistil, which consists of the ovary. The ovary, in turn, contains one to many ovules which become seeds after fertilization by way of pollination. When the ovules are fertilized, the ovary swells up and becomes what is known as the fruit.

Back in the day, when flowering plants first started developing fruits, they had leaves called carpels that had ovules lined up at the margins. Eventually these leaves rolled inward and enclosed the ovules, creating ovaries. In some plants the ovaries fused together, creating the sections we see in many fruits like oranges or tomatoes. Each section of an orange is actually a carpel.

Orange fruit develops from the ovary in the flower. In fact, all the fruits develop that way.

The orange ovary is compartmentalized i.e. it has a number of Chambers. As a result of this the fruit shows sections.

Each section is a compartment.

because somehow they know that it makes life a lot easier when they are in sections

So they can be more organized and not get lost.