Introduction
Biology plays a crucial role in the General Science section of the NDA & CDS examinations conducted by Union Public Service Commission. Among the most frequently asked topics are Human Digestive System and Respiratory System, as they form the foundation of human physiology. Understanding these systems helps candidates answer direct MCQs, assertion–reason, and concept-based questions with confidence.
This class introduces the basic structure, functions, and processes involved in digestion and respiration, keeping the syllabus and exam pattern of NDA CDS 1 2026 in focus.
Digestive System – Overview
The digestive system is responsible for breaking down complex food substances into simpler, absorbable forms that provide energy, growth, and repair to the body.
Key Points Covered
- Major organs: Mouth, Oesophagus, Stomach, Small Intestine, Large Intestine
- Digestive glands: Salivary glands, Liver, Pancreas
- Types of digestion: Mechanical and Chemical
- Important enzymes and their functions (amylase, pepsin, trypsin, bile)
- Absorption of nutrients mainly in the small intestine (villi)
Exam Focus:
MCQs are commonly asked on digestive enzymes, functions of bile, role of pancreas, and site of absorption.
Respiratory System – Overview
The respiratory system enables the process of breathing and gas exchange, supplying oxygen to the body and removing carbon dioxide.
Key Points Covered
- Parts of respiratory system: Nose, Trachea, Bronchi, Lungs, Alveoli
- Difference between breathing and respiration
- Mechanism of inhalation and exhalation
- Role of alveoli in gaseous exchange
- Transport of oxygen by haemoglobin
Exam Focus:
Questions often appear on alveoli structure, oxygen transport, role of diaphragm, and respiratory volumes.
Importance for NDA CDS 1 2026 Exam
- Biology contributes easy and scoring questions in the exam.
- Digestive and respiratory systems are high-weightage topics.
- Most questions are NCERT-based and concept-driven.
- Clear understanding helps in quick elimination of wrong options in MCQs.
- Repeated questions are seen from enzymes, organs, and functions.
Conclusion
The Digestive and Respiratory Systems are fundamental to human survival and equally important for NDA CDS 1 2026 preparation. A strong conceptual base in these topics allows candidates to solve MCQs accurately and efficiently. By focusing on key terms, organ functions, and physiological processes, aspirants can maximize their score in the Biology section. This introductory class sets the groundwork for deeper learning and effective exam-oriented preparation in upcoming sessions.
