What is true about all sponges without exception ?

Options

A. They are all marine
B. They have flagellated collar cells
C. They have a mixed skeleton consisting of spicules and spongin fibres
D. They reproduce only asexually by budding

Answer

B

Explanation

Sponges are all aquatic, mostly marine but few fresh water forms also exist. Choanocytes or collar cells are only present in sponges.
Sponges usually have a skeleton consisting of spicules or spongin fibres.
sponges reproduce asexually by budding, gemmules and reproduce sexually too.