1. a polysaccharide-based substance that forms the exoskeleton of arthropods.
 ( larva )
 2. an early stage in the development of an animal or plant
(hydroskeleton)  
3. the period of time offspring is carried in the womb before birth
(chitin)
  4. gamete-producing organ in animals
(gonad)
  5. support and movement structure of animals that is maintained by water or body fluid (gestation period)
  6. an early growth stage or phase of life of an organism that undergoes metamorphosis
(embryo)