Question

1. which of the following cnidarian classes is made entirely of animals that live in the polyp stage?

ctenidaria
scyphozoa
anthozoa
hydrozoa

Explanation:

To solve this, we analyze each Cnidarian class:

• Ctenidaria: Not a Cnidarian class (it’s Ctenophora, a different phylum).
• Scyphozoa: Jellyfish, primarily medusa stage (some polyp in life cycle, but not entirely polyp).
• Anthozoa: Includes corals, sea anemones, etc.—all members exist only in the polyp stage (no medusa stage).
• Hydrozoa: Includes organisms with both polyp and medusa stages (e.g., hydras, some have medusa forms).

Answer:

C. Anthozoa