Creating a comprehensive question book for **Class 8 CBSE Science** involves covering all the major concepts across the three sections: **Physics**, **Chemistry**, and **Biology**. Each chapter can have different types of questions: **multiple-choice questions (MCQs)**, **short answer questions**, **long answer questions**, and **application-based questions** to cater to a variety of student learning styles. Below is a structured question book for the entire Class 8 Science syllabus.

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## **Class 8 Science - CBSE Question Book**

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### **Chapter 1: Crop Production and Management**

#### **Multiple Choice Questions (MCQs)**:
1. The practice of growing different crops in the same field in succession is known as:
   - a) Irrigation
   - b) Crop rotation
   - c) Harvesting
   - d) Manuring

2. Which tool is used for ploughing?
   - a) Sickle
   - b) Harrow
   - c) Hoe
   - d) Plough

#### **Short Answer Questions**:
1. Why is irrigation necessary in agriculture?
2. What are the different methods of irrigation?

#### **Long Answer Questions**:
1. Explain the process of crop production starting from soil preparation to harvesting.
2. Describe the importance of storage and preservation of grains after harvesting.

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### **Chapter 2: Microorganisms: Friend and Foe**

#### **Multiple Choice Questions (MCQs)**:
1. Which of the following is a disease caused by a virus?
   - a) Tuberculosis
   - b) Malaria
   - c) AIDS
   - d) Typhoid

2. Which microorganism is used in the production of curd?
   - a) Yeast
   - b) Virus
   - c) Lactobacillus
   - d) Fungi

#### **Short Answer Questions**:
1. Name two useful microorganisms and describe their use.
2. What is food preservation? Mention two methods of preserving food.

#### **Long Answer Questions**:
1. Describe how microorganisms can be both useful and harmful.
2. Explain how vaccines work to protect against diseases.

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### **Chapter 3: Synthetic Fibres and Plastics**

#### **Multiple Choice Questions (MCQs)**:
1. Rayon is also known as:
   - a) Artificial silk
   - b) Polyester
   - c) Nylon
   - d) Wool

2. Which of the following is a thermosetting plastic?
   - a) Polythene
   - b) Bakelite
   - c) Nylon
   - d) PVC

#### **Short Answer Questions**:
1. What are synthetic fibres? Give two examples.
2. Why should we reduce the use of plastics?

#### **Long Answer Questions**:
1. Explain the types of synthetic fibres with examples.
2. What are the harmful effects of plastics on the environment? Suggest measures to reduce plastic pollution.

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### **Chapter 4: Materials: Metals and Non-metals**

#### **Multiple Choice Questions (MCQs)**:
1. Which metal is liquid at room temperature?
   - a) Iron
   - b) Mercury
   - c) Copper
   - d) Lead

2. Non-metals are generally:
   - a) Malleable
   - b) Good conductors of electricity
   - c) Non-conductors of electricity
   - d) Ductile

#### **Short Answer Questions**:
1. Give two uses of metals and non-metals.
2. What happens when metals react with acids?

#### **Long Answer Questions**:
1. Differentiate between metals and non-metals based on their physical and chemical properties.
2. Explain how rusting occurs and how it can be prevented.

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### **Chapter 5: Coal and Petroleum**

#### **Multiple Choice Questions (MCQs)**:
1. Which of the following is a fossil fuel?
   - a) Coal
   - b) Petroleum
   - c) Natural gas
   - d) All of the above

2. CNG is mainly composed of:
   - a) Methane
   - b) Ethane
   - c) Butane
   - d) Propane

#### **Short Answer Questions**:
1. What is the difference between exhaustible and inexhaustible resources?
2. What is refining of petroleum?

#### **Long Answer Questions**:
1. Describe the formation of coal and petroleum.
2. What are the harmful effects of burning fossil fuels on the environment?

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### **Chapter 6: Combustion and Flame**

#### **Multiple Choice Questions (MCQs)**:
1. The lowest temperature at which a substance catches fire is called its:
   - a) Ignition temperature
   - b) Flash point
   - c) Boiling point
   - d) Melting point

2. Which of the following is an example of rapid combustion?
   - a) Burning of LPG
   - b) Burning of paper
   - c) Photosynthesis
   - d) Rusting

#### **Short Answer Questions**:
1. Define combustion and list three types of combustion.
2. What is a fire extinguisher? How does it work?

#### **Long Answer Questions**:
1. Explain the structure of a flame. Draw a neat diagram.
2. How can the occurrence of fire accidents be prevented? Describe three safety measures.

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### **Chapter 7: Conservation of Plants and Animals**

#### **Multiple Choice Questions (MCQs)**:
1. Which of the following is an endangered species?
   - a) Elephant
   - b) Tiger
   - c) Sparrow
   - d) Cat

2. A place where animals are protected in their natural habitat is called:
   - a) Zoo
   - b) Wildlife sanctuary
   - c) Aquarium
   - d) National park

#### **Short Answer Questions**:
1. What is deforestation? How does it affect the environment?
2. Define biodiversity. Why is it important to conserve it?

#### **Long Answer Questions**:
1. Explain the causes and effects of deforestation.
2. Discuss the various steps taken by the government to conserve wildlife.

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### **Chapter 8: Cell – Structure and Functions**

#### **Multiple Choice Questions (MCQs)**:
1. The basic unit of life is the:
   - a) Organ
   - b) Cell
   - c) Tissue
   - d) Organ system

2. The control center of a cell is called the:
   - a) Mitochondria
   - b) Nucleus
   - c) Cytoplasm
   - d) Cell membrane

#### **Short Answer Questions**:
1. What is the function of the cell membrane?
2. Name two organelles found only in plant cells.

#### **Long Answer Questions**:
1. Explain the structure and functions of a plant cell with a labeled diagram.
2. Differentiate between prokaryotic and eukaryotic cells.

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### **Chapter 9: Reproduction in Animals**

#### **Multiple Choice Questions (MCQs)**:
1. The process of fusion of male and female gametes is called:
   - a) Fertilization
   - b) Pollination
   - c) Fragmentation
   - d) Budding

2. Animals that give birth to young ones are called:
   - a) Oviparous
   - b) Viviparous
   - c) Amphibians
   - d) Fish

#### **Short Answer Questions**:
1. What is the difference between external and internal fertilization?
2. What is metamorphosis? Give an example.

#### **Long Answer Questions**:
1. Explain the process of sexual reproduction in animals.
2. Describe the life cycle of a frog.

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### **Chapter 10: Reaching the Age of Adolescence**

#### **Multiple Choice Questions (MCQs)**:
1. The phase of life when a person becomes capable of reproduction is called:
   - a) Menopause
   - b) Puberty
   - c) Childhood
   - d) Old age

2. The hormone responsible for male characteristics is:
   - a) Estrogen
   - b) Testosterone
   - c) Progesterone
   - d) Insulin

#### **Short Answer Questions**:
1. What are the changes that occur during adolescence?
2. Explain the role of hormones in reproduction.

#### **Long Answer Questions**:
1. What are the physical and emotional changes during puberty? How can adolescents deal with these changes?
2. Explain the significance of maintaining personal hygiene during adolescence.

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### **Chapter 11: Force and Pressure**

#### **Multiple Choice Questions (MCQs)**:
1. The SI unit of force is:
   - a) Joule
   - b) Newton
   - c) Pascal
   - d) Watt

2. Pressure is defined as:
   - a) Force per unit area
   - b) Force per unit volume
   - c) Area per unit force
   - d) Mass per unit volume

#### **Short Answer Questions**:
1. Define force. What are the effects of force on an object?
2. What is atmospheric pressure?

#### **Long Answer Questions**:
1. Explain the types of forces with examples.
2. Discuss the relationship between force, pressure, and area with an example.

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### **Chapter 12: Friction**

#### **Multiple Choice Questions (MCQs)**:
1. Friction always acts in the:
   - a) Same direction as motion
   - b) Opposite direction of motion
   - c) Perpendicular to motion
   - d) Random direction

2. Which of the following reduces friction?
   - a) Sandpaper