CBSE Class 10 Science: Life Processes — Important Questions with Answers 2026

Short Answer Questions (2-3 Marks)

• Q: What are the different modes of nutrition? Explain autotrophic nutrition.
  Ans: Modes: (1) Autotrophic — organisms make their own food. Example: green plants (photosynthesis). (2) Heterotrophic — organisms depend on others for food. Types: Saprophytic (feed on dead matter — fungi), Parasitic (feed on living host — Cuscuta), Holozoic (ingest and digest food — humans). Autotrophic nutrition: Plants use CO₂, H₂O, and sunlight to produce glucose. 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. Occurs in chloroplasts.
• Q: Describe the process of digestion in humans.
  Ans: Digestion involves: (1) Mouth — saliva contains amylase, breaks starch → maltose. Teeth mechanically break food. (2) Stomach — HCl kills bacteria, pepsin breaks proteins → peptides. Churning mixes food. (3) Small intestine (duodenum) — bile (from liver) emulsifies fats; pancreatic juice contains trypsin (proteins), lipase (fats), amylase (starch). (4) Small intestine (jejunum/ileum) — final digestion and absorption through villi. (5) Large intestine — absorbs water, forms faeces. (6) Rectum/Anus — egestion.
• Q: Explain double circulation in humans. Why is it necessary?
  Ans: Double circulation: Blood passes through the heart twice in one complete cycle. Pulmonary circulation: Right ventricle → Pulmonary artery → Lungs (oxygenation) → Pulmonary veins → Left atrium. Systemic circulation: Left ventricle → Aorta → Body organs → Vena cava → Right atrium. Necessity: It ensures complete separation of oxygenated and deoxygenated blood, maintaining efficient oxygen delivery to body cells. Essential for warm-blooded animals with high energy needs.

Long Answer / Application Questions (4-6 Marks)

• Q: Draw a diagram of the human respiratory system and explain the mechanism of breathing.
  Ans: Parts: Nostrils → Nasal passage → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli (in lungs). Mechanism: Inhalation — diaphragm contracts (flattens), intercostal muscles contract, rib cage expands, lung volume increases, air pressure decreases, air rushes in. Exhalation — diaphragm relaxes (dome-shaped), intercostal muscles relax, rib cage contracts, lung volume decreases, air pushed out. Gas exchange: In alveoli — O₂ diffuses into blood, CO₂ diffuses out.

Exam Tips for This Chapter

• Revise all definitions and laws from Life Processes — they are commonly asked as 1-2 mark questions
• Practice diagrams related to Life Processes — neat labelled diagrams carry 2-3 marks
• For numericals, always show formula → substitution → answer with correct units
• Previous year analysis shows Life Processes carries 8-12 marks in the board exam