Question

Metamerism is characterised of
A Platyhelminthes
B Mollusca
C Porifera
D Annelida

Answer 1

Hint: Annulus describe rings, the organisms belonging to the phylum Annelida family have their bodies divided into circular segments or can be said as rings, this segmentation is both internal as well as external.

Complete answer:
A - The flatworms, Platyhelminthes, or platyhelminthes are a phylum of relatively simple bilaterian, unsegmented, and soft-bodied invertebrates.
B - Mollusca is the second-largest phylum present in invertebrate animals after the Arthropod. The members are called ad molluscs or mollusks. The number of fossil species is estimated between 60,000 along with 100,000 additional species.
C – Sponges are the members of the phylum Porifera, further described as a basal Metazoan clade as a sister of the Diploblasts. They are considered to be multicellular organisms that have bodies which are full of pores as well as channels allowing water to circulate through them. They also include jelly-like mesohyl sandwiched between the two thin layers of cells.
D- Annelida is a group generally referred to as segmented worms, as well as they are found worldwide from the deepest marine sediments to the soil and sand in our city parks and yards.

So, the correct answer to this question is option D- 'Annelida'.

Note: In earthworm, the body includes about 100-120 ring-like segments they are called metameres. It displays true segmentation corresponding with internal segmentation. Cockroach also shows the same metameric segmentation. In their body anterior have few segments and are specialized to form the head. Such metamerism is known as heteronomous metamerism.