Sea sponges can have hearts.

The story behind the answer

False. Sea sponges (phylum Porifera) have no heart—or any true organs. They lack circulatory, nervous, and digestive systems. Instead, specialized cells called choanocytes beat tiny flagella to create water currents through their pores, bringing in oxygen and food and carrying away waste. Mobile cells (amoebocytes) then distribute nutrients within the sponge.

Sponges are among the simplest multicellular animals and act like living filters, processing vast amounts of water relative to their size. Remarkably, if passed through a fine sieve, their cells can reassemble into a functioning sponge. Memory tip: Sponges pump, they don’t pulse—no heart needed.