Sponges (phylum: Porifera) are animals that possess feeding cells called collar cells. These cells have a central flagellum surrounded by a collar of microvilli. The collar filters organic matter out of the water column. Which protist shares a more recent common ancestor with the poriferans

Choanoflagellates

Explanation:

Protists are organisms that have both plant and animal like characteristics. Some protists develop more plant like characteristics and others more animal like characteristics. Choanoflagellates are the protists which looks like animals called sponges. These protists are single celled organisms. Their function is similar to collar cells of the sponges that is they produce current in water that draws water and food particles via the body of sponges and they filter the food particles through their microvilli.