Question
CMDARIA &CTEMOPTIORA Which of the following describes hydrozoans? a. Box jellyfish b. Have stinging cells c. Have zooids d. Polyp dominant
Answer
4.4
(254 Votes)
Oswald
Expert · Tutor for 3 years
Answer
B. Have stinging cells, C. Have zooids, D. Polyp dominant
Explanation
Hydrozoans are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most living in salt water. The alternatives provided in the question describe different characteristics of marine fauna:a. Box jellyfish: These are a type of jellyfish, but they are not hydrozoans. They belong to the class Cubozoa. b. Have stinging cells: Hydrozoans do have stinging cells (called cnidocytes), but the presence of stinging cells is common to all cnidarians, not just hydorozoans; it includes other groups like jellyfish and anemones.c. Have zooids: Some hydrozoans are colonial and consist of different types of zooids, each specialized for a different function such as feeding, reproduction, defense.d. Polyp dominant: Hydrozoa generally have a 'polyp' phase that gives rise to asexual individuals. This makes this option a definitive distinguishing factor for hydrozoans.So, options b, c, and d accurately describe hydrozoans. Stinging cells are a feature of all Cnidaria. The presence of different zooids in colonies and a lifecycle that primarily consists of polyps are common features of hydrozoans.