- What is the primary characteristic of sponges in the class Hexactinellida?
- A) They have siliceous spicules.
- B) They have calcium carbonate spicules.
- C) They lack spicules.
- D) They have organic spicules.
- Answer: A) They have siliceous spicules.
- Hexactinellida sponges are commonly known as:
- A) Glass sponges
- B) Stone sponges
- C) Marine sponges
- D) Freshwater sponges
- Answer: A) Glass sponges.
- Which type of body plan is predominantly found in Hexactinellida sponges?
- A) Asconoid
- B) Syconoid
- C) Leuconoid
- D) Both A and B
- Answer: C) Leuconoid.
- What type of spicules do Hexactinellida sponges possess?
- A) Calcitic spicules
- B) Siliceous spicules with a hexactinal structure
- C) Organic spicules
- D) All of the above
- Answer: B) Siliceous spicules with a hexactinal structure.
- Where are Hexactinellida sponges primarily found?
- A) Freshwater habitats
- B) Terrestrial environments
- C) Deep marine environments
- D) Intertidal zones
- Answer: C) Deep marine environments.
- Which of the following is a common characteristic of Hexactinellida sponges?
- A) They have a soft, jelly-like texture.
- B) They can be found in both freshwater and marine environments.
- C) They exhibit a high degree of structural complexity.
- D) They are exclusively colonial.
- Answer: C) They exhibit a high degree of structural complexity.
- Hexactinellida sponges typically reproduce through which method?
- A) Asexual reproduction only
- B) Sexual reproduction only
- C) Both asexual and sexual reproduction
- D) Budding only
- Answer: C) Both asexual and sexual reproduction.
- What is the ecological role of Hexactinellida sponges in marine environments?
- A) Primary producers
- B) Filter feeders
- C) Predators
- D) Decomposers
- Answer: B) Filter feeders.
- Hexactinellida sponges are characterized by their:
- A) High metabolic rates
- B) Thick walls
- C) Simple body structure
- D) Unique hexactinal spicules
- Answer: D) Unique hexactinal spicules.
- Which of the following structures is essential for water circulation in Hexactinellida sponges?
- A) Osculum
- B) Choanocytes
- C) Spongocoel
- D) All of the above
- Answer: D) All of the above.
- What type of symmetry do Hexactinellida sponges exhibit?
- A) Bilateral symmetry
- B) Radial symmetry
- C) Asymmetry
- D) None of the above
- Answer: B) Radial symmetry.
- Which of the following is a genus of sponges in the class Hexactinellida?
- A) Clathrina
- B) Euplectella
- C) Oscillatoria
- D) Chlamydomonas
- Answer: B) Euplectella.
- What larval stage do Hexactinellida sponges undergo?
- A) Planula
- B) Parenchymella
- C) Trochophore
- D) Veliger
- Answer: A) Planula.
- What is a common feature of the habitat where Hexactinellida sponges are found?
- A) Shallow waters
- B) High current areas
- C) Deep ocean floors
- D) Coral reefs
- Answer: C) Deep ocean floors.
- Which of the following best describes the physical structure of Hexactinellida sponges?
- A) Gelatinous and soft
- B) Rigid and glassy
- C) Flexible and leathery
- D) Hard and calcareous
- Answer: B) Rigid and glassy.
- In terms of biodiversity, Hexactinellida sponges are considered to be:
- A) Highly diverse
- B) Moderately diverse
- C) Low diversity
- D) Non-diverse
- Answer: C) Low diversity.
- What type of feeding mechanism do Hexactinellida sponges utilize?
- A) Absorption
- B) Filter feeding
- C) Photosynthesis
- D) Predation
- Answer: B) Filter feeding.
- What is the primary mode of locomotion for Hexactinellida sponges?
- A) Swimming
- B) Crawling
- C) They are sessile (non-moving).
- D) Burrowing
- Answer: C) They are sessile (non-moving).
- Which feature differentiates Hexactinellida from other sponge classes?
- A) Presence of siliceous spicules
- B) Presence of calcium carbonate spicules
- C) Presence of unique hexactinal spicules
- D) Presence of a soft body
- Answer: C) Presence of unique hexactinal spicules.
- Hexactinellida sponges are often found at what depths in the ocean?
- A) Less than 10 meters
- B) 10 to 100 meters
- C) 100 to 1000 meters
- D) Greater than 1000 meters
- Answer: D) Greater than 1000 meters.
- What is the primary threat to Hexactinellida sponges in their natural habitat?
- A) Pollution
- B) Overfishing
- C) Habitat destruction
- D) All of the above
- Answer: D) All of the above.
- What kind of skeleton do Hexactinellida sponges have?
- A) Calcareous skeleton
- B) Siliceous skeleton
- C) Organic skeleton
- D) No skeleton
- Answer: B) Siliceous skeleton.
- Hexactinellida sponges are primarily composed of which type of cells?
- A) Epithelial cells
- B) Choanocytes
- C) Nerve cells
- D) Muscle cells
- Answer: B) Choanocytes.
- Which of the following is NOT a characteristic of Hexactinellida sponges?
- A) Siliceous spicules
- B) Presence of oscula
- C) Complex canal systems
- D) Ability to photosynthesize
- Answer: D) Ability to photosynthesize.
- What is the role of the mesohyl in Hexactinellida sponges?
- A) Water circulation
- B) Nutrient transport and structural support
- C) Gas exchange
- D) All of the above
- Answer: B) Nutrient transport and structural support.
- Hexactinellida sponges are known for their:
- A) Rapid growth
- B) Long lifespan
- C) Bright coloration
- D) Ability to regenerate quickly
- Answer: B) Long lifespan.
- What unique feature allows Hexactinellida sponges to filter water efficiently?
- A) Large size
- B) Complex canal system
- C) High reproductive rate
- D) None of the above
- Answer: B) Complex canal system.
- Which ecological role do Hexactinellida sponges fulfill?
- A) Primary consumers
- B) Secondary producers
- C) Decomposers
- D) Filter feeders and habitat providers
- Answer: D) Filter feeders and habitat providers.
- Hexactinellida sponges can be found in which marine environments?
- A) Coral reefs
- B) Deep-sea habitats
- C) Intertidal zones
- D) Coastal lagoons
- Answer: B) Deep-sea habitats.
- Which of the following is a significant aspect of the biology of Hexactinellida sponges?
- A) They are strictly freshwater species.
- B) They possess true tissues.
- C) They have a unique reproductive cycle.
- D) They can survive in extreme temperatures.
- Answer: C) They have a unique reproductive cycle.