Choanoflagellates while single-celled, resemble the specialized cells that line the channels of sponges, which are considered by many to be the most primitive living animal.

Choanoflagellates 虽然是单细胞的， 但类似于排列在海绵通道中的特殊细胞，海绵被许多人认为是最原始的活体动物。