- What is the defining characteristic of the phylum Cnidaria?
- A) Presence of a notochord
- B) Presence of cnidocytes
- C) Bilateral symmetry
- D) Exoskeleton
Answer: B) Presence of cnidocytes
- Which of the following is NOT a class within the phylum Cnidaria?
- A) Hydrozoa
- B) Scyphozoa
- C) Cephalopoda
- D) Anthozoa
Answer: C) Cephalopoda
- What type of body symmetry do cnidarians exhibit?
- A) Bilateral symmetry
- B) Radial symmetry
- C) Asymmetry
- D) None of the above
Answer: B) Radial symmetry
- Which structure in cnidarians is used for capturing prey?
- A) Tentacles
- B) Nematocysts
- C) Medusa
- D) Polyp
Answer: B) Nematocysts
- In which form do jellyfish primarily exist?
- A) Polyp
- B) Medusa
- C) Planula
- D) Sporophyte
Answer: B) Medusa
- Which class of Cnidaria includes sea anemones and corals?
- A) Hydrozoa
- B) Scyphozoa
- C) Anthozoa
- D) Cubozoa
Answer: C) Anthozoa
- The life cycle of a jellyfish typically alternates between which two forms?
- A) Planula and medusa
- B) Polyp and medusa
- C) Adult and larval
- D) Nematocyst and medusa
Answer: B) Polyp and medusa
- Which of the following is a common habitat for Cnidarians?
- A) Freshwater
- B) Terrestrial
- C) Marine environments
- D) All of the above
Answer: C) Marine environments
- What type of digestion occurs in cnidarians?
- A) Extracellular digestion
- B) Intracellular digestion
- C) Both extracellular and intracellular digestion
- D) Fermentation
Answer: C) Both extracellular and intracellular digestion
- Which of the following organisms is classified as a hydrozoan?
- A) Sea anemone
- B) Portuguese man o’ war
- C) Box jellyfish
- D) Coral
Answer: B) Portuguese man o’ war
- What is the role of the mesoglea in cnidarians?
- A) Muscle contraction
- B) Support and buoyancy
- C) Digestion
- D) Gas exchange
Answer: B) Support and buoyancy
- Which type of Cnidarian is known for its box-shaped medusa?
- A) Hydrozoa
- B) Scyphozoa
- C) Anthozoa
- D) Cubozoa
Answer: D) Cubozoa
- Corals form symbiotic relationships with which type of algae?
- A) Diatoms
- B) Dinoflagellates
- C) Green algae
- D) Blue-green algae
Answer: B) Dinoflagellates
- Which of the following is a characteristic feature of the class Scyphozoa?
- A) Small size
- B) Dominance of the polyp stage
- C) Large, umbrella-shaped medusae
- D) Freshwater habitat
Answer: C) Large, umbrella-shaped medusae
- What kind of reproductive strategy is commonly observed in Cnidarians?
- A) Asexual reproduction
- B) Sexual reproduction
- C) Both asexual and sexual reproduction
- D) Budding only
Answer: C) Both asexual and sexual reproduction
- What structure is responsible for the locomotion of medusa forms?
- A) Tentacles
- B) Mesoglea
- C) Bell-shaped body
- D) Oral arms
Answer: C) Bell-shaped body
- In Cnidarians, which structure serves as the mouth and anus?
- A) Gastrovascular cavity
- B) Osculum
- C) Medusa
- D) Umbrella
Answer: A) Gastrovascular cavity
- Which class of Cnidarians is known for its colonial lifestyle?
- A) Hydrozoa
- B) Scyphozoa
- C) Anthozoa
- D) Cubozoa
Answer: A) Hydrozoa
- What is the main function of the tentacles in Cnidarians?
- A) Defense
- B) Prey capture
- C) Respiration
- D) Reproduction
Answer: B) Prey capture
- Which of the following statements about coral reefs is true?
- A) They are formed only by hard corals.
- B) They provide habitats for many marine species.
- C) They are found exclusively in freshwater.
- D) They do not require sunlight to thrive.
Answer: B) They provide habitats for many marine species.
- What is a common feature of the class Anthozoa?
- A) They have a free-swimming larval stage.
- B) They lack a medusa stage.
- C) They primarily exist as medusae.
- D) They are exclusively marine.
Answer: B) They lack a medusa stage.
- Which Cnidarian is known for its powerful sting and is often found in warm waters?
- A) Sea anemone
- B) Box jellyfish
- C) Coral
- D) Hydra
Answer: B) Box jellyfish
- What type of symmetry do Cnidarians exhibit?
- A) Bilateral symmetry
- B) Radial symmetry
- C) Asymmetry
- D) Pentaradial symmetry
Answer: B) Radial symmetry
- Which type of reproduction involves the formation of a polyp from a planula larva?
- A) Asexual reproduction
- B) Sexual reproduction
- C) Budding
- D) Fragmentation
Answer: B) Sexual reproduction
- What is the primary purpose of the nematocysts found in Cnidarians?
- A) Respiration
- B) Defense and capturing prey
- C) Digestion
- D) Locomotion
Answer: B) Defense and capturing prey
- What form does a hydra predominantly exist in?
- A) Medusa
- B) Polyp
- C) Planula
- D) Sporophyte
Answer: B) Polyp
- Which class of Cnidaria is primarily composed of small, freshwater species?
- A) Hydrozoa
- B) Scyphozoa
- C) Anthozoa
- D) Cubozoa
Answer: A) Hydrozoa
- Which of the following structures is used for locomotion in some jellyfish?
- A) Tentacles
- B) Mesenteries
- C) Bell
- D) Oral arms
Answer: C) Bell
- Which type of organism is typically found in the class Hydrozoa?
- A) Sea pens
- B) Sea fans
- C) Hydra
- D) Both A and B
Answer: D) Both A and B
- What is the habitat of most Cnidarians?
- A) Terrestrial environments
- B) Freshwater bodies
- C) Marine environments
- D) All of the above
Answer: C) Marine environments
Classes of Cnidaria