How do flowers come up every year?¿?

My mom and dad planted these tulips (I think that's what they're: yellow flower type plants) around our mailbox and every year they come up, how is it that they continue to come up after all these years?¿

How do flowers come up every year?¿?
they are perennial bulbs, plant once and they grow year after year, difference between annuals and perennials, annuals need to be planted every year (in most cases) then there are biannuals....
Reply:It's what they do....plants have been doing it for millions of years. The grass in your yard does it too.