Question

38. Which one of the following is not a characteristic
feature of sponges?
(a) Cellular level of organisation
(b) Presence of ostia
(c) Intracellular digestion
(d) Body supported by chitin
(e) Indirect development
(Kerala PMT)​

Answer 1

Explanation:

ANSWER

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'.

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