Inflorescence

An inflorescence is a flowering stem. The term is most used for a group or cluster of flowers arranged on a stem. An inflorescence is the reproductive portion of a plant; each plant bears its flowers in a specific pattern.
Whereas gymnosperms are mostly wind-pollinated, flowering plants are mostly pollinated by insects. There are some exceptions to this, for instance grasses are wind-pollinated. However, as a general rule, flowering plants rely on animals for their pollination.
Most flowers are pollinated by animals, usually insects. To be pollinated, "a flower needs to be seen". Most insects have good colour vision, including vision in the ultra-violet (which humans do not have).
That is the reason many flowers have attractive colours. 
Sometimes there is just a close bunch of flowers (e.g. "Antirrhinum") on a "spike". Sometimes the inflorescence is so tight it looks like one single flower. What you see as a single daisy is actually made of several hundred tiny flowers packed together. This kind of inflorescence is called a pseudanthium ("false flower").
Advantages.
The advantages of the inflorescence mode is all about reproduction compared to a single primitive flower of the "Magnolia" type.