Question

question 3 (10 points)
which organisms are radially symmetrical; they have tissues and stinging cells. ?

a) flatworms

b) mollusks

c) sponges

d) cnidarians

e) echinoderms

f) annelids

g) roundworms

h) chordates
i) arthropods

Explanation:

• Flatworms (a) have bilateral symmetry.
• Mollusks (b) have bilateral symmetry (except some gastropods during development).
• Sponges (c) are asymmetrical (or have very simple symmetry).
• Cnidarians (d) are radially symmetrical and have stinging cells (nematocysts) and tissues.
• Echinoderms (e) have secondary radial symmetry (larvae are bilaterally symmetrical).
• Annelids (f) have bilateral symmetry.
• Roundworms (g) have bilateral symmetry.
• Chordates (h) have bilateral symmetry.
• Arthropods (i) have bilateral symmetry.

Answer:

d) cnidarians