An opening
All Cnidarians can reproduce asexually through either budding, splitting down the center, and some can bot bud and split themselves. Some Cnidarians reproduce sexually as well, but not all.
Cnidarians all have stinging cells called nematocysts with which to catch their prey.
The characteristic that gives cnidarians their name is: cnidarian means "nettle" and nettles are plants that release stinging barbs into the skin. All cnidarians have stinging cell's. Cnidarians have complex tissues, a gut for digesting food, and a nervous system.
All the organisms in phylum Cnidaria are aquatic.
small cnidarians and big cnidarians
sac-like
Flatworms don't belong to cnidarians .They belong to Platyhelminthis . All others are cnidarians .
The cnidarians are in the Kindom family
cnidarians have no nervous system
Yes, cnidarians are invertebrates.
They all came at the same time.
I don't feel like answering it