What helps circulate water through the sponge?

Water circulation through a sponge is primarily facilitated by the movement of specialized cells called choanocytes, which have flagella that create a water current. This current draws water into the sponge through tiny pores called ostia, allowing for the intake of nutrients and oxygen while expelling waste through larger openings called oscula. The porous structure of the sponge, along with its unique cellular arrangement, aids in maximizing water flow throughout its body.