Invertebrate Phyla Practice Questions
19 free Invertebrate Phyla practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which phylum is characterized by true segmentation of the body?
- A Arthropoda
- B Mollusca
- C Annelida
- D Echinodermata
Correct answer: Annelida
Annelids exhibit true metameric segmentation. Their body is divided into repeated segments, each with similar internal structures.
Which phylum possesses jointed appendages and a chitinous exoskeleton?
- A Annelida
- B Mollusca
- C Echinodermata
- D Arthropoda
Correct answer: Arthropoda
Arthropods have jointed appendages and a hard exoskeleton made of chitin. This provides protection and aids movement.
Which phylum is known for having a soft body often protected by a calcareous shell?
- A Mollusca
- B Annelida
- C Arthropoda
- D Echinodermata
Correct answer: Mollusca
Molluscs have soft, unsegmented bodies, often enclosed within a calcareous shell. Examples include snails and clams.
Which phylum exhibits radial symmetry in adults and bilateral symmetry in larvae?
- A Annelida
- B Arthropoda
- C Mollusca (soft-bodied)
- D Echinodermata
Correct answer: Echinodermata
Echinoderms show radial symmetry as adults but bilateral symmetry during larval stages. This reflects their evolutionary origin.
Which structure is used for locomotion in annelids?
- A Parapodia or setae
- B Tube feet
- C Muscular foot for gliding
- D Jointed legs
Correct answer: Parapodia or setae
Annelids use parapodia or setae for movement. These structures help in crawling and anchorage.
Which phylum includes organisms like cockroaches, crabs, and insects?
- A Annelida
- B Mollusca
- C Echinodermata
- D Arthropoda
Correct answer: Arthropoda
Arthropoda is the largest phylum and includes insects, crustaceans, and arachnids. They are highly diverse and widespread.
Which body cavity type is present in annelids?
- A Acoelomate
- B Pseudocoelomate
- C True coelom
- D Hemocoel
Correct answer: True coelom
Annelids are true coelomates. Their body cavity is fully lined by mesoderm.
Which type of circulatory system is found in arthropods?
- A Closed
- B Absent
- C Double circulation
- D Open circulation
Correct answer: Open circulation
Arthropods have an open circulatory system. Blood flows freely in body cavities rather than through vessels.
Which organ is used for respiration in many molluscs?
- A Gills
- B Trachea
- C Skin
- D Book lungs
Correct answer: Gills
Most aquatic molluscs respire through gills. Some terrestrial forms use lungs.
Which system is unique to echinoderms?
- A Water vascular system
- B Digestive system
- C Blood circulatory system
- D Nervous system
Correct answer: Water vascular system
Echinoderms possess a water vascular system. It helps in locomotion, feeding, and respiration.
Which phylum includes animals with a muscular foot used for movement?
- A Mollusca
- B Annelida
- C Arthropoda
- D Echinodermata
Correct answer: Mollusca
Molluscs possess a muscular foot that aids in locomotion. It is a defining feature of the group.
Which phylum has an exoskeleton that must be shed periodically?
- A Annelida
- B Mollusca
- C Arthropoda
- D Echinodermata
Correct answer: Arthropoda
Arthropods undergo molting or ecdysis to shed their exoskeleton. This allows growth.
Which type of symmetry is found in annelids?
- A Bilateral symmetry
- B Radial symmetry
- C Asymmetry
- D Spherical symmetry
Correct answer: Bilateral symmetry
Annelids exhibit bilateral symmetry. Their body can be divided into two equal halves along one plane.
Which phylum includes animals like starfish and sea urchins?
- A Echinodermata
- B Mollusca
- C Annelida
- D Arthropoda (insects)
Correct answer: Echinodermata
Echinodermata includes marine animals like starfish and sea urchins. They are exclusively marine.
Which phylum shows a hemocoel instead of a true coelom?
- A Annelida
- B Arthropoda
- C Mollusca
- D Echinodermata
Correct answer: Arthropoda
Arthropods have a hemocoel, where blood fills body cavities. It replaces the true coelom.
Which phylum has a radula for feeding?
- A Annelida
- B Mollusca
- C Arthropoda
- D Echinodermata
Correct answer: Mollusca
Molluscs have a radula, a rasping organ used for feeding. It is absent in some bivalves.
Which type of fertilization is common in echinoderms?
- A Internal fertilization
- B External fertilization
- C Asexual reproduction only
- D Parthenogenesis
Correct answer: External fertilization
Echinoderms generally show external fertilization. Gametes are released into water.
Which phylum has closed circulatory system among the following?
- A Arthropoda
- B Annelida
- C Mollusca
- D Echinodermata
Correct answer: Annelida
Annelids have a closed circulatory system. Blood flows through a network of vessels.
Which phylum is considered the largest in terms of number of species?
- A Annelida
- B Mollusca
- C Arthropoda
- D Echinodermata
Correct answer: Arthropoda
Arthropoda is the largest phylum, with the highest number of species. It includes insects, which are extremely diverse.