18.Which of the following Annelid is Dioecious- A. Nereis B. Pheretima C. Hirudinaria D. Both b & c
Option A. Nereis are osmoconformers. Nereids are dioecious and they release their haploid gametes into the water medium, a process called spawning. Moreover, upon fertilization and mitotic divisions of the zygote, Nereids form a larval stage which is similar to that of molluscs i.e. a trochophore larva.
