Hydras are members of which class of Cnidaria?Group of answer choicesClass ScyphozoaClass AnthozoaClass PolyplacaphoraClass Hydrozoa

Step 1: Break Down the Problem

To determine which class of Cnidaria hydras belong to, we need to analyze the available options and identify the correct classification.

Step 2: Relevant Concepts

1. Cnidaria: A phylum that includes organisms like jellyfish, corals, and hydras, characterized by the presence of cnidocytes (stinging cells).
2. Classes of Cnidaria:
   • Class Scyphozoa: Includes jellyfish.
   • Class Anthozoa: Includes corals and sea anemones.
   • Class Polyplacophora: This is not a class of Cnidaria; it refers to a class of mollusks.
   • Class Hydrozoa: This class includes hydras and is characterized by both polyp and medusa stages.

Step 3: Analysis and Detail

• The correct classification of hydras is explicitly part of the Class Hydrozoa within the phylum Cnidaria.
• The options presented include three relevant classes of Cnidaria and one unrelated class (Polyplacophora).

Step 4: Verify and Summarize

Upon reviewing the options and confirming that hydras are classified under Hydrozoa, we find that the other classes do not include hydras.

Final Answer

Class Hydrozoa