Which of the following best describes a key difference between the first cnidarians and sponges (phylum Porifera)?

Which one of the following terms applies to the phylum Cnidaria?

Which of the following is true about the phylum Cnidaria?

Which characteristic is shared by cnidarians and flatworms?

Sponges lack __________.

Some digestion in sponges takes place in the __________.

Which of the following is/are characteristic of sponges?

Which of the following features is characteristic of the poriferan (sponge) body plan or life history?