In which of the following organisms is the genetic material organized into chromosomes?

Which one of the following does not have a larval stage in its life cycle?

Trochophore larva is found in

Read the following four statements $(A-D)$:
$(A)$ Annelids possess only longitudinal muscles which help in locomotion.
$(B)$ Nephridia do not help in excretion and osmoregulation.
$(C)$ Closed type circulatory system is present in most of annelids.
$(D)$ Members of phylum Annelida are triploblastic,metamerically segmented,and acoelomate.
How many of the above statements are incorrect?

Which of the following respiratory pigments is found in the coelomic fluid of certain annelids?

Which organism belongs to the class Oligochaeta?