Number of molting present in nematodes is:

• Nematodes, also known as roundworms, undergo four molts during their life cycle. Molting is the process of shedding the old cuticle (exoskeleton) and forming a new one as the nematode grows. Each molt marks a transition between different developmental stages:
First Molt: Occurs within the egg or shortly after hatching.
Second Molt: Transitions the nematode from a juvenile to an adult stage.
Third Molt: Often associated with further development and maturation of reproductive organs.
Fourth Molt: Marks the final adult stage of the nematode.