Cnidaria

Feeding:

•  feed in several ways
• predation on corals, absorbing dissolved organic chemicals, filtering food particles out of water, getting nutrients from algae with their cells
• depend mostly on absorbing dissolved nutrients uses tentacles to capture food
• tentacles have rows of cilia whose beating creates currents that flow towards the mouth

Respiration:

• there are no respiratory organs and cells layers absorb oxygen and expel carbon dioxide into the water

Circulation: 

• they lack a circulatory system because they do not need one

Excretion:

• canal like cavity in they bodies for ingestion, digestion
• gas is eliminated by diffusion
• solid waste is dissolved 

Response/ Movement:

• muscle surrounding cavity relaxes and contracts, causing it to move back and forth
• as water moves in one direction, it moves in opposite way

Reproduction:

• sexual and asexual
• assexually with diffusion
• sexually with the ova and sperm being released from the gonads and gastroderms