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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the defining characteristic of cnidarians?
A
tentacles
B
radial symmetry
C
stinging cells
D
larva
Explanation: 

Detailed explanation-1: -Nearly all (about 99 percent) cnidarians are marine species. Cnidarians contain specialized cells known as cnidocytes (“stinging cells”) containing organelles called nematocysts (stingers). These cells are present around the mouth and tentacles, and serve to immobilize prey with toxins contained within the cells.

Detailed explanation-2: -Cnidocytes (“cnidos is Greek for “stinging nettle”), common to species in the diverse phylum Cnidaria, can launch a toxic barb or blob or enable cnidarians to stun prey or deter invaders. Cnidarians are the only animals that have cnidocytes, but lots of animals have neurons, Babonis said.

Detailed explanation-3: -Cnidarians exhibit a specific characteristic – tentacles with stinging nematocytes which serve as small harpoons which react to stimuli by giving out tiny stinging cells which can poison and hook potential prey. Cnidarians do not show bones and a central nervous system, rather have a nerve net.

Detailed explanation-4: -All Cnidaria are aquatic, mostly marine, organisms. They all have tentacles with stinging cells called nematocysts that they use to capture food. Cnidarians only have two body layers, the ectoderm and endoderm, separated by a jelly-like layer called the mesoglea. Most Cnidarians have radial symmetry.

Detailed explanation-5: -Cnidarians possess stinging cells, called cnidocytes or cnidoblasts, which contain stinging capsules or nematocytes. These cnidocytes are present on the tentacles and the body, and are used for anchorage, defense and for the capture of prey.

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