- Placozoa are primarily known as:
- A) Flat animals
- B) Jelly-like organisms
- C) Simple multicellular animals
- D) Marine mammals
Answer: C) Simple multicellular animals
- What is the most well-known species of Placozoa?
- A) Trichoplax adhaerens
- B) Placozoa simplex
- C) Turritopsis dohrnii
- D) Chordata
Answer: A) Trichoplax adhaerens
- Placozoa primarily inhabit:
- A) Freshwater environments
- B) Terrestrial habitats
- C) Marine environments
- D) Deep-sea vents
Answer: C) Marine environments
- The body structure of Placozoa is best described as:
- A) Cylindrical
- B) Radially symmetrical
- C) Flat and irregular
- D) Segmented
Answer: C) Flat and irregular
- Placozoans primarily feed on:
- A) Larger prey
- B) Algae and organic debris
- C) Other marine animals
- D) Detritus
Answer: B) Algae and organic debris
- Which of the following best describes the movement of Placozoa?
- A) Swimming using fins
- B) Gliding over surfaces
- C) Burrowing into sediments
- D) Jet propulsion
Answer: B) Gliding over surfaces
- Placozoans reproduce primarily by:
- A) Budding
- B) Binary fission
- C) Sexual reproduction
- D) Fragmentation
Answer: A) Budding
- The body of a Placozoan is composed of how many cell layers?
- A) One
- B) Two
- C) Three
- D) Four
Answer: B) Two
- Which of the following is a characteristic feature of Placozoa?
- A) Presence of a circulatory system
- B) Ability to form shells
- C) Lack of a true body cavity
- D) Complex organ systems
Answer: C) Lack of a true body cavity
- The outer layer of a Placozoan is primarily composed of:
- A) Epithelial cells
- B) Muscle cells
- C) Nerve cells
- D) Ciliated cells
Answer: A) Epithelial cells
- Placozoa are classified within which larger animal group?
- A) Metazoa
- B) Protozoa
- C) Coelenterata
- D) Annelida
Answer: A) Metazoa
- The feeding process in Placozoa is characterized by:
- A) Filter feeding
- B) Phagocytosis
- C) Absorption through the body surface
- D) Active predation
Answer: B) Phagocytosis
- The term “placozoan” is derived from Greek, meaning:
- A) Flat animal
- B) Simple creature
- C) Tiny organism
- D) Soft body
Answer: A) Flat animal
- Which of the following statements about Placozoa is TRUE?
- A) They have complex nervous systems.
- B) They can undergo both sexual and asexual reproduction.
- C) They have a defined skeletal structure.
- D) They exhibit bilateral symmetry.
Answer: B) They can undergo both sexual and asexual reproduction.
- The interior of a Placozoan is filled with a jelly-like substance known as:
- A) Mesoglea
- B) Coelom
- C) Parenchyma
- D) Protoplasm
Answer: A) Mesoglea
- Placozoans are known for their ability to:
- A) Regenerate lost body parts
- B) Form colonies
- C) Swim against currents
- D) Live in extreme conditions
Answer: A) Regenerate lost body parts
- The ecological role of Placozoa primarily includes:
- A) Predators in marine ecosystems
- B) Decomposers of organic material
- C) Primary producers
- D) Symbiotic relationships with coral
Answer: B) Decomposers of organic material
- Placozoa are often found in which specific marine environment?
- A) Open ocean
- B) Coral reefs
- C) Tide pools
- D) Rocky shores
Answer: C) Tide pools
- The body of Placozoa lacks which of the following structures?
- A) Tissues
- B) Organs
- C) Cell layers
- D) Sensory cells
Answer: B) Organs
- Placozoans are believed to be one of the most:
- A) Complex multicellular organisms
- B) Primitive multicellular animals
- C) Adaptable marine organisms
- D) Colorful marine species
Answer: B) Primitive multicellular animals
- The primary method of locomotion for Placozoa involves:
- A) Ciliary movement
- B) Contractile muscles
- C) Pseudopodia
- D) Jet propulsion
Answer: A) Ciliary movement
- Which of the following is a primary characteristic of Placozoa?
- A) Presence of gills
- B) Photosynthetic capability
- C) Simple body plan
- D) Highly developed nervous system
Answer: C) Simple body plan
- The body of a Placozoan can often change shape by:
- A) Fluid movement
- B) Rapid cell division
- C) External pressure
- D) Muscle contraction
Answer: A) Fluid movement
- Placozoans primarily reproduce by:
- A) Sexual reproduction
- B) Asexual budding
- C) Binary fission
- D) Fragmentation
Answer: B) Asexual budding
- What type of symmetry do Placozoans exhibit?
- A) Bilateral symmetry
- B) Radial symmetry
- C) Asymmetry
- D) Pentamerous symmetry
Answer: C) Asymmetry
- Placozoans are significant for studies in evolutionary biology because they:
- A) Show advanced multicellularity
- B) Represent early branching in the animal kingdom
- C) Have complex behaviors
- D) Are closely related to vertebrates
Answer: B) Represent early branching in the animal kingdom
- The cells that facilitate feeding in Placozoans are known as:
- A) Gastrodermal cells
- B) Ciliated cells
- C) Mesenchymal cells
- D) Epithelial cells
Answer: B) Ciliated cells
- Which statement about the habitat of Placozoa is true?
- A) They prefer deep oceanic waters.
- B) They are found in nutrient-poor environments.
- C) They thrive in areas with abundant organic material.
- D) They require high light conditions to survive.
Answer: C) They thrive in areas with abundant organic material.
- Placozoa are most closely related to which of the following groups?
- A) Cnidarians
- B) Flatworms
- C) Annelids
- D) Sponges
Answer: D) Sponges
- The first scientific description of Placozoa was published in which year?
- A) 1824
- B) 1883
- C) 1970
- D) 2000
Answer: B) 1883