[Campbell Biology P.741] According to the text, which statement correctly describes the typi... | Practice Question

According to the text, which statement correctly describes the typical life cycle stages of different cnidarian groups within Medusozoa?

  • A: Most hydrozoans primarily exist in the medusa stage, while scyphozoans and cubozoans have a dominant polyp stage.
  • B: Scyphozoans and cubozoans predominantly spend their lives in the medusa stage, whereas most hydrozoans typically alternate between conspicuous polyp and medusa forms.
  • C: Cubozoans lack a medusa stage, existing only as polyps, unlike hydrozoans which are exclusively medusae.
  • D: All Medusozoans, including hydrozoans, scyphozoans, and cubozoans, strictly exist only in the medusa form.

Explanation

The text states: 'Unlike hydrozoans, most scyphozoans and cubozoans spend the majority of their life cycles in the medusa stage.' And for hydrozoans: 'Most hydrozoans alternate between the polyp and medusa forms, as seen in the life cycle of Obelia... The polyp stage... is more conspicuous than the medusa.' This aligns perfectly with option B.