All questions of Structural Organisation in Animals for NEET Exam

Respiratory Mechanism in Adult Frogs
Adult frogs utilize multiple methods for respiration, primarily due to their amphibious nature. Here's a breakdown of the correct mechanisms:
1. Cutaneous Respiration
- Frogs can absorb oxygen directly through their moist skin.
- This allows them to breathe while submerged in water or when on land, making skin a significant respiratory surface.
2. Buccopharyngeal Respiration
- The lining of the buccopharyngeal cavity also facilitates gas exchange.
- Frogs can gulp air and exchange gases in this cavity, functioning as an additional respiratory method.
3. Pulmonary Respiration
- Adult frogs possess lungs which they use for breathing air.
- When on land, they rely on their lungs to extract oxygen from the air efficiently.
Incorrect Options for Adult Frogs
4. Tracheal Respiration
- This method is not present in frogs; tracheal systems are typically found in insects.
- Frogs do not have spiracles or tracheae for respiration.
5. Branchial Respiration
- This type of respiration is relevant only during the tadpole stage when they have gills.
- Adult frogs do not utilize branchial respiration as they develop lungs.
Conclusion
The correct answer is option 'A', which includes cutaneous, buccopharyngeal, and pulmonary respiration methods. This multi-faceted respiratory system allows frogs to thrive in diverse environments, effectively utilizing both skin and lungs while transitioning between aquatic and terrestrial habitats.

Understanding the Male Frog Reproductive System
Frogs, particularly Rana tigrina, possess a fascinating reproductive system. Let's analyze the statements to identify which one is NOT incorrect.
Statement Analysis
- a) The testes are paired and located near the kidneys
- This statement is correct. The testes are indeed paired and situated near the kidneys in male frogs.
- b) Vasa efferentia connect the testis to the ureter
- This statement is incorrect. Vasa efferentia actually connect the testis to the kidneys, not the ureter.
- c) The ureter acts as urinogenital duct in males
- This statement is NOT incorrect. In male frogs, the ureter does serve a dual purpose, functioning as both a urinary and genital duct, allowing for the passage of sperm and urine.
- d) Bidder's canal is present in males only
- This statement is incorrect. Bidder's canal is associated with the reproductive system of males, but it can also play a role in females.
Conclusion
The correct answer, option 'C', highlights the unique function of the ureter in male frogs. It is significant to understand that while the ureter serves as a urinogenital duct, it is essential in the reproductive process, facilitating the transfer of sperm during mating. Understanding these anatomical relationships is crucial for comprehending frog reproduction in a broader biological context.