Flies undergo which type of metamorphosis?

Flies undergo complete metamorphosis, which is characterized by four distinct life stages: egg, larva, pupa, and adult. In this process, the organism completely changes its form between these stages. When a fly lays its eggs, the larvae (commonly known as maggots) hatch and feed, growing into larger larvae. After this larval stage, they enter the pupal stage, during which they undergo significant transformation, ultimately emerging as adult flies. This is in contrast to gradual metamorphosis, where the changes occur more continuously without a distinct pupal stage.

The other options do not accurately describe the life cycle of flies. Gradual metamorphosis would suggest a more continuous transformation without the distinct separation of pupal and adult forms. Continuous and complex metamorphosis are not standard terms used in entomology to describe the developmental processes of flies or similar insects. Understanding the complete metamorphosis that flies experience is important for pest control professionals to effectively manage these pests at various life stages.