Nutrition in Animals — Class 7 Science NCERT Solutions (Free)
Free step-by-step NCERT solutions for Class 7 Science chapter "Nutrition in Animals" — 4 important questions with detailed answers for CBSE board exam preparation.
TL;DR: Free step-by-step NCERT solutions for Class 7 Science chapter "Nutrition in Animals" — 4 important questions with detailed answers for CBSE board exam…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
NCERT Solutions for Class 7 Science — Nutrition in Animals. Step-by-step answers to all 4 textbook questions from this chapter, written for CBSE board preparation and free to use.
Nutrition in Animals — All 4 Questions Solved
Q1. जानवरों को पोषण की क्या आवश्यकता होती है?
जानवरों को जीवित रहने के लिए पोषण की आवश्यकता होती है। कार्बोहाइड्रेट ऊर्जा देते हैं। प्रोटीन शरीर की मरम्मत और वृद्धि में मदद करते हैं। वसा ऊर्जा का भंडार हैं। विटामिन और खनिज विभिन्न कार्यों में सहायक हैं। पानी जीवन के लिए आवश्यक है।
Q2. विभिन्न जानवर क्या खाते हैं?
शाकाहारी जानवर पौधे खाते हैं जैसे गाय, हिरण। मांसाहारी जानवर मांस खाते हैं जैसे शेर, चीता। सर्वाहारी जानवर पौधे और मांस दोनों खाते हैं जैसे मनुष्य, सूअर। इनके दाँत और पाचन तंत्र उनके भोजन के अनुसार ढले होते हैं।
Q3. मानव पाचन तंत्र कैसे काम करता है?
भोजन मुँह से प्रवेश करता है। दाँत भोजन को तोड़ते हैं। लार में एंजाइम होता है। भोजन घुटकी से होकर पेट में जाता है। पेट में पाचन होता है। छोटी आँत में भोजन को अवशोषित किया जाता है। बड़ी आँत से बचा हुआ भोजन निकलता है।
Q4. दाँतों के प्रकार क्या हैं?
मनुष्य के दाँतों के प्रकार हैं: कृन्तन दाँत, रदन दाँत और चबाने वाले दाँत। कृन्तन दाँत भोजन को काटते हैं। रदन दाँत भोजन को फाड़ते हैं। चबाने वाले दाँत भोजन को पीसते हैं। विभिन्न दाँत विभिन्न कार्य करते हैं।
Nutrition in Animals — Practice MCQs with Answers
Attempt these 20 multiple-choice questions after working through the solutions above. Each carries the correct option and the reasoning behind it, so a wrong answer tells you which idea to revisit.
MCQ 1. What is the primary role of saliva in human digestion?
- A. To absorb water
- B. To digest proteins
- C. To moisten food and break down starch
- D. To store undigested food
Answer: C. To moisten food and break down starch — Saliva moistens the food, making it easier to chew and swallow. It also contains salivary amylase, an enzyme that starts the digestion of starch.
MCQ 2. Which of the following components of gastric juice helps in killing bacteria and making the medium acidic for protein digestion?
- A. Pepsin
- B. Mucus
- C. Hydrochloric acid
- D. Bile
Answer: C. Hydrochloric acid — Hydrochloric acid present in the gastric juice kills bacteria that enter with food and provides an acidic medium necessary for the enzyme pepsin to act on proteins.
MCQ 3. The process of taking food into the body is called:
- A. Digestion
- B. Ingestion
- C. Egestion
- D. Assimilation
Answer: B. Ingestion — Ingestion is the process by which an organism takes food into its body.
MCQ 4. Ruminants like cows can digest cellulose, which humans cannot. Which part of their digestive system helps in this process?
- A. Oesophagus
- B. Small intestine
- C. Rumen
- D. Abomasum
Answer: C. Rumen — The rumen is the first and largest chamber in the stomach of ruminants, where cellulose is partially digested by the action of certain bacteria.
MCQ 5. How does an Amoeba capture its food?
- A. Using tentacles
- B. Using a proboscis
- C. Using pseudopodia
- D. Using cilia
Answer: C. Using pseudopodia — Amoeba uses temporary finger-like projections called pseudopodia to engulf its food particles, forming a food vacuole.
MCQ 6. Where does the complete digestion of carbohydrates, proteins, and fats occur in the human digestive system?
- A. Stomach
- B. Large intestine
- C. Oesophagus
- D. Small intestine
Answer: D. Small intestine — The small intestine is the site where the complete digestion of all components of food (carbohydrates, proteins, and fats) takes place.
MCQ 7. What is the main function of the villi present on the inner walls of the small intestine?
- A. To produce digestive enzymes
- B. To absorb water
- C. To increase the surface area for absorption of digested food
- D. To store undigested food
Answer: C. To increase the surface area for absorption of digested food — Villi are finger-like projections that increase the inner surface area of the small intestine, thus maximizing the efficiency of absorption of digested nutrients.
MCQ 8. Which type of teeth are primarily used for biting and cutting food?
- A. Molars
- B. Premolars
- C. Incisors
- D. Canines
Answer: C. Incisors — Incisors are the front teeth used for cutting and biting food.
MCQ 9. Which gland secretes bile juice, which helps in the digestion of fats?
- A. Pancreas
- B. Salivary gland
- C. Liver
- D. Stomach wall
Answer: C. Liver — The liver is the largest gland in the body and secretes bile juice, which is stored in the gall bladder and plays a crucial role in emulsifying fats.
MCQ 10. The process by which food moves down the food pipe (oesophagus) is called:
- A. Vomiting
- B. Chewing
- C. Peristalsis
- D. Swallowing
Answer: C. Peristalsis — Peristalsis is the rhythmic contraction and relaxation of the muscles in the walls of the oesophagus, which pushes food downwards towards the stomach.
MCQ 11. What is "cud" in the context of ruminant digestion?
- A. The undigested waste material
- B. The partially digested food returned to the mouth for re-chewing
- C. The fully digested food absorbed in the small intestine
- D. The liquid secreted by the rumen
Answer: B. The partially digested food returned to the mouth for re-chewing — Cud is the partially digested food that ruminants bring back into their mouth from the rumen for further chewing, a process called rumination.
MCQ 12. While pepsin digests proteins in the stomach, trypsin acts on proteins in the small intestine. What is the main reason they function in different parts of the digestive system?
- A. Pepsin only acts on carbohydrates, while trypsin acts on proteins.
- B. Pepsin requires an acidic medium, while trypsin requires an alkaline medium.
- C. Trypsin is produced by the stomach, while pepsin is produced by the pancreas.
- D. Pepsin only acts on simple proteins, while trypsin acts on complex proteins.
Answer: B. Pepsin requires an acidic medium, while trypsin requires an alkaline medium. — Pepsin functions optimally in the highly acidic environment of the stomach (due to HCl), while trypsin, secreted by the pancreas, requires an alkaline or basic environment in the small intestine to be active.
MCQ 13. The process by which digested food passes into the blood vessels in the walls of the intestine is called:
- A. Ingestion
- B. Egestion
- C. Absorption
- D. Assimilation
Answer: C. Absorption — Absorption is the process where digested food molecules pass through the intestinal wall and enter the bloodstream.
MCQ 14. The pancreas secretes pancreatic juice, which acts on:
- A. Only carbohydrates
- B. Only proteins
- C. Only fats
- D. Carbohydrates, proteins, and fats
Answer: D. Carbohydrates, proteins, and fats — Pancreatic juice contains enzymes (like amylase, trypsin, lipase) that act on carbohydrates, proteins, and fats, respectively, to aid in their digestion.
MCQ 15. Which of the following is NOT a primary function of the large intestine?
- A. Absorption of water
- B. Formation of faeces
- C. Absorption of some salts
- D. Digestion of fats
Answer: D. Digestion of fats — The large intestine's primary functions are the absorption of water and some salts from the undigested food material, and the formation and temporary storage of faeces. It does not perform significant digestion of fats or other macromolecules.
MCQ 16. Animals are classified as which type of feeders based on their nutrition?
- A. Autotrophs
- B. Heterotrophs
- C. Photosynthetic
- D. Chemosynthetic
Answer: B. Heterotrophs — Animals cannot synthesize their own food and rely on other organisms for nutrition, making them heterotrophs.
MCQ 17. Apart from mixing food with saliva, what is another important function of the tongue during digestion?
- A. Producing digestive enzymes
- B. Helping to swallow food
- C. Absorbing nutrients
- D. Storing food temporarily
Answer: B. Helping to swallow food — The tongue helps in tasting food, mixing it with saliva, and pushing it towards the pharynx to initiate the swallowing process.
MCQ 18. The process of removing undigested food from the body is called:
- A. Absorption
- B. Assimilation
- C. Egestion
- D. Digestion
Answer: C. Egestion — Egestion is the final step in nutrition, where the undigested waste material is expelled from the body.
MCQ 19. What protects the inner lining of the stomach from the corrosive action of hydrochloric acid?
- A. Villi
- B. Bile
- C. Mucus
- D. Pepsin
Answer: C. Mucus — The inner lining of the stomach is protected by a layer of mucus, which prevents the hydrochloric acid from damaging the stomach wall.
MCQ 20. Which of these statements about ruminants and rumination is INCORRECT?
- A. They have a four-chambered stomach.
- B. They chew their food thoroughly before swallowing it the first time.
- C. Microorganisms in the rumen help digest cellulose.
- D. They bring back partially digested food to the mouth for re-chewing.
Answer: B. They chew their food thoroughly before swallowing it the first time. — Ruminants typically swallow their food quickly with little chewing (bolus) and store it in the rumen. They then bring it back later to chew it thoroughly as "cud."
How to Use These Solutions
Attempt each question yourself first and only then compare with the worked answer. Marks in the CBSE board exam are awarded for the METHOD as much as the final result, so reproduce the steps rather than memorising the last line. Where a solution states a law, a formula or a definition, learn that wording — examiners look for it.
Related practice for this chapter: chapter MCQs, previous-year questions, revision notes and sample papers.