Multiple choice

The canal system is a characteristic feature of

  1. echinoderms

  2. sponges

  3. coelenterates

  4. mollusks

  5. fish

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

All the cavities in a sponge's body are intercommunicating and are collectively referred to as the canal system. Thus, the canal system helps the sponge in nutrition, respiration and excretion.