Question

The cellular level of body organisation is found in

• A. jellyfishes
• B. sponges
• C. roundworms
• D. flatworms

Answer 1

The correct option is B sponges

Body organisation is one of the criteria based on which animals have been further divided into phyla. Body organisation may be cellular, tissue-level, organ-level or organ system level.

In lower animals such as sponges, there are no specialized structures to perform specific functions. There are groups of cells that take care of these functions. Hence we say that they have a cellular level of organisation.

Jellyfishes have cells grouped together to perform specific functions. This group of cells is called tissues. Hence jellyfishes have tissue level of organisation.

Flatworms exhibit organ level of organisation, where several tissues join to form organs responsible for a specific function. We can see the beginning of the formation of organ system in this phylum, such as a primitive nervous system and the reproductive system.

Roundworms show organ system level of organization where several organs group together to form an organ system, such as the reproductive system, excretory system, etc.