Skip to content

ZOOLOGY

Zoology questions grouped for topic-by-topic study, covering animal diversity, organ systems, reproduction and related concepts. Take one topic at a time to build up coverage, or dip in for a short practice session. Answers are included so you can measure progress as you revise.

45 questions

Why do echinoderms exhibit bilateral symmetry in their larval stage but radial symmetry as adults?

Larval Stage: Bilateral symmetry enables free-swimming larvae to balance and move efficiently in open water. Adult Stage: Adult echinoderms live on the seafloor (benthic zone). Pentaradial symmetry allows them to feed and detect surroundings equally from all directions.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which of the following best describes gel electrophoresis?

Gel electrophoresis is used to separate DNA fragments based on size using an electric field. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which process is responsible for the degradation of maternal hormones, leading to menstruation if no fertilization occur

If fertilization does not occur, the withdrawal of progesterone and estrogen leads to the degeneration of the endometrium and the onset of menstruation.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which phenomenon explains the rapid diversification of species from a common ancestor into various ecological niches?

Adaptive radiation refers to the evolution of different species from a common ancestor, each adapting to different environments. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which phylum includes animals with an open circulatory system?

Arthropods have an open circulatory system where the blood directly bathes organs in a hemocoel. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which respiratory disorder is caused by exposure to dust particles in industries such as stone grinding?

Silicosis is an occupational respiratory disorder caused by long-term exposure to fine dust particles, leading to lung fibrosis. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which of the following statements about respiratory disorders is correct?

Silicosis is a chronic occupational lung disease caused by prolonged exposure to silica dust. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which of the following statements about muscle contraction is correct?

Myosin heads form cross-bridges with actin filaments during muscle contraction. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which contraceptive method works by suppressing ovulation and altering rvical mucus consistency?

Oral contraceptive pills contain hormones that suppress ovulation and alter rvical mucus to prevent fertilization. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which of the following is incorrect about Bt cotton?

Bacillus thuringiensis (Bt) cotton provides pest resistance but does not improve the nutritional value of cotton seeds. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which hormone is secreted by the parathyroid gland and increases blood calcium levels?

PTH increases blood calcium levels by stimulating calcium release from bones and increasing absorption in the intestines. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

Which of the following statements about cancer lls is incorrect?

Cancer lls can spread to other parts of the body through a process called metastasis. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.