Question

Which of the following is a false statement?
A. All sponges are hermaphrodites
B. Choanocytes are helpful in locomotion
C. Sponges are multicellular organisms
D. Internal fertilization

Answer 1

A sponge comes under the phylum Porifera. It is one of the simplest animals with many cells, but they don’t have a mouth, heart, brain or muscles. They are sessile, that means they cannot move from one place to another place the way most animals can. A sponge is an animal that grows in a single spot like most of the plants do.

Complete answer:
By supportively moving their flagella, choanocytes filter elements out of the water and also into the spongocoel and through it out via the osculum. This increases respiratory and digestive functions for the sponge. By pulling in $O{}_2$and nutrition and letting a swiftejection of $CO{}_2$and other surplus products.
Sponges are normally immovable as adults and spend their lives attached to a fixed bedrock. They don’t display any movement over huge distances as do free-swimming marine invertebrates. Though sponge cells can creep along bedrock via organizational plasticity.
So, here the statement “Choanocytes are helpful in locomotion” is False.
Therefore, here the correct answer is option B.
Additional Information:
Option A – All sponges are hermaphrodites:Sponges are normally hermaphroditic (that means having male and female germ cells in a single animal). But some sponge species are sequential hermaphrodites (that means having male and female germ cells that develop at different times in the same animal).
So, it is a true statement.
Therefore, this option is not the correct one.
Option C – Sponges are multicellular organisms: Yes the sponges are multicellular organisms.
So, it is also a true statement.
Therefore, this option is not the correct one.
Option D – Internal fertilization: In sponges fertilization is internal where the sperm of one sponge floats and enters into another sponge through choanocytes.

So, it is also a true statement.
Therefore, this option is not the correct one.

Note:
Sea Sponges are not plants. They are animals. They have been in the sea for $500$ million years. Sea Sponges are immovable but they filter lots of water for food or plankton and oxygen. Sea Sponges are the simplest among all of the multicellular organisms.