In case of poriferans, the spongocoel is lined with flagellated cells called
- mesenchymal cells
- oscula
- ostia
- choanocytes
Answer
(4) choanocytes
Solution
As per NCERT, in poriferans (sponges) water enters through minute pores (ostia) into a central cavity, the spongocoel, and leaves through the osculum.
The spongocoel and the canals are lined with flagellated collar cells called choanocytes.
∴ Ostia and oscula are openings, not cells; mesenchymal cells lie in the body wall.
Answer: (4)