Question

Which one of the following is not the characteristic feature of sponges?

• A. Cellular level of organisation
• B. Body supported by chitin
• C. Presence of ostia
• D. Intracellular digestion
• E. Indirect development

Answer 1

The correct option is B Body supported by chitin

A. Sponges belong to phylum porifera and are the most primitive of multicellular animals. These animals exhibit only cellular levels of body organisation and thus, are considered as the simplest forms among the metazoans.

B. The body of sponges is supported by spicules, which may be calcareous or siliceous, and spongin fibres. On the other hand, chitin is present in the cell wall of fungi.

C. Ostia (singular: ostium) are the inhalant pores in sponges through which water enters the body.

D. Sponges do not have a digestive system. The food is directly ingested by them with the help of choanocytes which is then transferred to food vacuoles and broken down into simpler substances. Hence, nutrition in sponges is intracellular as it is occurring inside the cells.

E. Development in sponges is indirect through larval stages known as Parenchymula and Amphiblastula.

Hence, statement B is incorrect.

So, the correct answer is 'Body supported by chitin'.