Phylum Orthonectida MCQs

  • Orthonectida are primarily classified as which type of organism?
    • A) Protozoa
    • B) Marine invertebrates
    • C) Parasites
    • D) Plants
      Answer: C) Parasites
  • What type of body structure do orthonectids exhibit?
    • A) Bilateral symmetry
    • B) Radial symmetry
    • C) Asymmetrical body
    • D) Segmented body
      Answer: A) Bilateral symmetry
  • Orthonectids are known to primarily inhabit which environment?
    • A) Freshwater
    • B) Terrestrial
    • C) Marine
    • D) Aerial
      Answer: C) Marine
  • What is the main mode of nutrition for orthonectids?
    • A) Photosynthesis
    • B) Absorption of nutrients from the host
    • C) Filter feeding
    • D) Predation
      Answer: B) Absorption of nutrients from the host
  • Which of the following organisms are common hosts for orthonectids?
    • A) Mollusks
    • B) Echinoderms
    • C) Annelids
    • D) Arthropods
      Answer: C) Annelids
  • The life cycle of orthonectids is typically characterized by:
    • A) Complex metamorphosis
    • B) Direct development
    • C) Multiple larval stages
    • D) Asexual reproduction
      Answer: B) Direct development
  • Which of the following best describes the body structure of orthonectids?
    • A) Well-defined organs
    • B) Cellular organization without tissues
    • C) Possession of a true coelom
    • D) Presence of chitinous exoskeleton
      Answer: B) Cellular organization without tissues
  • Orthonectids are closely related to which group of organisms?
    • A) Cnidarians
    • B) Flatworms
    • C) Tardigrades
    • D) Nematodes
      Answer: B) Flatworms
  • The primary mode of reproduction in orthonectids is:
    • A) Asexual reproduction
    • B) Sexual reproduction
    • C) Budding
    • D) Fragmentation
      Answer: B) Sexual reproduction
  • What is a significant characteristic of orthonectids that aids in their parasitic lifestyle?
    • A) Ability to photosynthesize
    • B) Complex nervous system
    • C) Ability to penetrate host tissues
    • D) Hard exoskeleton
      Answer: C) Ability to penetrate host tissues
  • The developmental stages of orthonectids include:
    • A) Egg, larva, adult
    • B) Egg, juvenile, adult
    • C) Spore, larva, adult
    • D) Egg, trophozoite, adult
      Answer: A) Egg, larva, adult
  • Orthonectids are characterized by their unique method of:
    • A) Locomotion
    • B) Host manipulation
    • C) Feeding
    • D) Respiration
      Answer: B) Host manipulation
  • Which of the following is NOT a characteristic of orthonectids?
    • A) Bilateral symmetry
    • B) Lack of specialized respiratory structures
    • C) Complex digestive systems
    • D) Ability to reproduce in the host
      Answer: C) Complex digestive systems
  • Orthonectids are typically found in which part of their host?
    • A) In the muscles
    • B) In the digestive tract
    • C) In the blood
    • D) In the exoskeleton
      Answer: A) In the muscles
  • Which of the following statements about orthonectids is true?
    • A) They are strictly free-living organisms.
    • B) They have a complex lifecycle with many larval forms.
    • C) They are known for their ability to cause disease in hosts.
    • D) They lack any form of locomotion.
      Answer: C) They are known for their ability to cause disease in hosts.
  • The main ecological role of orthonectids is as:
    • A) Primary producers
    • B) Parasites in marine ecosystems
    • C) Decomposers
    • D) Filter feeders
      Answer: B) Parasites in marine ecosystems
  • Orthonectids are often studied for their:
    • A) Economic importance
    • B) Ecological impact on host species
    • C) Role in food chains
    • D) Aesthetic value
      Answer: B) Ecological impact on host species
  • What is the typical size range of orthonectids?
    • A) Microscopic to millimeter scale
    • B) Centimeter to meter scale
    • C) Meter to kilometer scale
    • D) Several meters long
      Answer: A) Microscopic to millimeter scale
  • The locomotion of orthonectids primarily involves:
    • A) Cilia
    • B) Pseudopodia
    • C) Flagella
    • D) Muscle contraction
      Answer: A) Cilia
  • Orthonectids are classified within which broader group?
    • A) Lophotrochozoa
    • B) Ecdysozoa
    • C) Deuterostomia
    • D) Parazoa
      Answer: A) Lophotrochozoa
  • What is the primary method by which orthonectids obtain nutrients from their hosts?
    • A) Filter feeding
    • B) Absorption through the skin
    • C) Parasitic feeding mechanisms
    • D) Symbiotic relationships
      Answer: C) Parasitic feeding mechanisms
  • Orthonectids can be identified by their distinct:
    • A) Coloration
    • B) Body plan
    • C) Feeding habits
    • D) Reproductive strategies
      Answer: B) Body plan
  • In terms of evolutionary significance, orthonectids provide insight into:
    • A) The evolution of parasitism
    • B) The evolution of complex multicellularity
    • C) The origin of vertebrates
    • D) The diversification of marine life
      Answer: A) The evolution of parasitism
  • Orthonectids are typically characterized by their:
    • A) High metabolic rates
    • B) Limited mobility
    • C) Ability to undergo metamorphosis
    • D) Lack of a nervous system
      Answer: D) Lack of a nervous system
  • Which of the following describes the reproduction process of orthonectids?
    • A) External fertilization
    • B) Internal fertilization
    • C) Parthenogenesis
    • D) Budding
      Answer: A) External fertilization
  • Orthonectids have a simple body structure composed mainly of:
    • A) Ectoderm and mesoderm
    • B) A single layer of cells
    • C) Endoderm only
    • D) Complex organ systems
      Answer: B) A single layer of cells
  • The primary scientific interest in orthonectids relates to their:
    • A) Habitat preferences
    • B) Role in marine food webs
    • C) Parasitic adaptations
    • D) Ecological relationships
      Answer: C) Parasitic adaptations
  • What kind of lifestyle do orthonectids lead?
    • A) Fully aquatic
    • B) Terrestrial
    • C) Parasitic
    • D) Saprophytic
      Answer: C) Parasitic
  • Which of the following best describes the reproductive strategy of orthonectids?
    • A) Asexual reproduction only
    • B) Sexual reproduction only
    • C) Both asexual and sexual reproduction
    • D) Budding only
      Answer: B) Sexual reproduction only
  • Orthonectids contribute to our understanding of:
    • A) Host-pathogen interactions
    • B) Evolution of terrestrial life
    • C) Plant-animal interactions
    • D) Marine conservation
      Answer: A) Host-pathogen interactions

 

Classes of Orthonectida

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