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Class 9 Science - Tissues Exercises Class 9 Science - Tissues Exercises 1. Define the term “tissue”. A tissue is a group of similar cells that work together to perform a specific function in the body. 2. How many types of elements together make up the xylem tissue? Name them. Xylem is made up of four types of elements: tracheids, vessels, xylem fibres, and xylem parenchyma. 3. How are simple tissues different from complex tissues in plants? Simple tissues are made up of only one type of similar cells, while complex tissues are made up of different types of cells working together. 4. Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall. - Parenchyma: Thin cell walls. - Collenchyma: Thick at corners. - Sclerenchyma: Very thick and hard cell walls. 5. What are the functions of the stomata? Stomata help in the exchange of gases and in the process of tra...

Class 9 Science - Tissues Exercises Class 9 Science - Tissues Exercises 1. Define the term “tissue”. A tissue is a group of similar cells that work together to perform a specific function in the body. 2. How many types of elements together make up the xylem tissue? Name them. Xylem is made up of four types of elements: tracheids, vessels, xylem fibres, and xylem parenchyma. 3. How are simple tissues different from complex tissues in plants? Simple tissues are made up of only one type of similar cells, while complex tissues are made up of different types of cells working together. 4. Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall. - Parenchyma: Thin cell walls. - Collenchyma: Thick at corners. - Sclerenchyma: Very thick and hard cell walls. 5. What are the functions of the stomata? Stomata help in the exchange of gases and in the process of tra...

Class 9 Science: Structure of the Atom - Exercises with Answers Class 9 Science: Structure of the Atom - Exercises with Answers Exercises and Answers 1. Compare the properties of electrons, protons, and neutrons. Electrons: Negatively charged, mass 1/1836 of proton, revolve around nucleus. Protons: Positively charged, mass 1 unit, present in the nucleus. Neutrons: Neutral, mass equal to proton, present in the nucleus. 2. What are the limitations of J.J. Thomson's model of the atom? It could not explain the results of scattering experiments and the stability of the atom, and why electrons do not radiate energy while revolving. 3. What are the limitations of Rutherford's model of the atom? It could not explain the stability of the atom as revolving electrons should lose energy and fall into the nucleus. 4. Describe Bohr's model of the atom. Electrons revolve in fixed circular orbits called energy levels without radiating energy. Energy is absorbed or e...

Chemistry Exercises and Solutions Chemistry Exercises and Solutions 1. Percentage Composition of Boron and Oxygen Question: A 0.240 g sample of a compound Y contains 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage by mass of boron and oxygen in compound Y. Answer: % B = (0.096 g / 0.240 g) × 100 = 40.0 % % O = (0.144 g / 0.240 g) × 100 = 60.0 % 2. Mass of CO₂ Formed and Governing Law Question: When 3.00 g of carbon burns in 8.00 g of oxygen, 11.00 g of carbon dioxide is formed. a) How many grams of CO₂ are formed when 3.00 g of carbon burns in 50.00 g of oxygen? b) Which law of chemical combination is illustrated by this observation? Answer: Moles of C = 3.00 g / 12.01 g·mol⁻¹ ≈ 0.250 mol Required O₂ = 0.250 mol × 32.00 g·mol⁻¹ = 8.00 g → C is limiting, O₂ in excess Moles of CO₂ = 0.250 mol → Mass = 0.250 mol × 44.01 g·mol⁻¹ = 11.00 g ...

Chemistry: Mixtures, Solubility & Separation Techniques Mixtures, Solubility & Separation Techniques Exercises & Detailed Answers 1. Separation Techniques 2. Making Tea 3. Solubility Data 4. Definitions 5. Mixture Classification 6. Pure Water Test 7. Which are Pure Substances? 8. Identify the Solutions 9. Tyndall Effect 10. Classify the Samples 11. Chemical Changes 1. Which Separation Technique? For each mixture, choose the best physical method to separate the components: (a) Sodium chloride from its solution in water (b) Ammonium chloride from a mixture containing sodium chloride & ammonium chloride (c) Small metal pieces in car engine oil (d) Different pigments from flower-petal extract (e) Butter from curd (f) Oil from water (g) Tea leaves from tea (h) Iron pins from ...

Class 6 Science Q&A Class 9 Science - Matter in Our Surroundings 1. Convert the following temperatures to the Celsius scale: Formula: °C = K - 273 (a) 293 K = 20°C (b) 470 K = 197°C 2. Convert the following temperatures to the Kelvin scale: Formula: K = °C + 273 (a) 25°C = 298 K (b) 373°C = 646 K 3. Give reason for the following observations: (a) Naphthalene balls disappear with time without leaving any solid because they undergo sublimation, changing directly from solid to gas. (b) We can get the smell of perfume sitting several metres away because its particles diffuse through air, a property of gases. 4. Arrange the following substances in increasing order of forces of attraction between the particles — water, sugar, oxygen. Increasing order: Oxygen < Water < Sugar. Gases have the least force of attraction, liquids have more, and solids have the most. 5. What is the...

Class 6 Science Q&A Class 8 Science - Light 1. Can you see anything in a dark room? Why? No, we cannot see objects in a dark room because there is no light. We need light to see things. 2. What is the difference between regular and diffused reflection? Regular reflection happens on smooth surfaces; light reflects evenly. Diffused reflection happens on rough surfaces; light scatters. 3. Write whether regular or diffused reflection happens: Polished wooden table – Regular Chalk powder – Diffused Cardboard surface – Diffused Marble floor with water – Regular Mirror – Regular Piece of paper – Diffused 4. State the laws of reflection. The angle of incidence is equal to the angle of reflection. The incident ray, reflected ray, and the normal lie in the same plane. 5. Activity to show incident ray, reflected ray, and normal. Shine a t...

Class 8 Science Q&A Class 8 Science - Some Natural Phenomena 1. Which of the following cannot be charged easily by friction? (b) A copper rod ✅ Copper is a metal and cannot hold charges by friction easily, unlike plastic or wool. 2. When a glass rod is rubbed with silk, what happens? (b) becomes positively charged while the cloth has a negative charge ✅ Electrons move from the rod to the silk cloth, making the rod positive and the cloth negative. 3. True or False (a) Like charges attract each other – ❌ False (b) A charged glass rod attracts a charged plastic straw – ✅ True (c) Lightning conductor cannot protect a building – ❌ False (d) Earthquakes can be predicted – ❌ False 4. Why do we hear crackling sounds when removing woolen clothes? It happens due to static electricity. Rubbing causes charge buildup, and the discharge makes a crackling sound. 5. Why does a charged ob...

Class 8 Science Q&A Class 8 Science - Chemical Effects of Electric Current 1. Fill in the blanks (a) Most liquids that conduct electricity are solutions of acids , bases , and salts . (b) The passage of an electric current through a solution causes chemical effects. (c) In copper sulphate solution, copper gets deposited on the plate connected to the negative terminal. (d) The process of depositing a layer of metal using electricity is called electroplating . 2. Why does the magnetic needle deflect when tester ends are dipped in a conducting solution? The magnetic needle deflects because electric current flows through the solution, creating a magnetic field around the tester. 3. Name three liquids that may cause deflection in the magnetic needle in the setup. Lemon juice Vinegar Saltwater 4. The bulb in the tester does not glow. What could be the reasons? ...

Class 6 Science Q&A Class 8 Science - Sound 1. Choose the correct answer. Sound can travel through: (d) solids, liquids and gases ✅ Sound needs a medium to travel. It can travel through solids, liquids, and gases, but not through vacuum. 2. Choose the correct answer. Voice of which of the following is likely to have minimum frequency? (c) A man ✅ A man’s voice has a low pitch and low frequency compared to others, so it has the minimum frequency. 3. Tick True or False (a) Sound cannot travel in vacuum. – ✅ True (b) The number of oscillations per second is called its time period. – ❌ False (c) If the amplitude of vibration is large, sound is feeble. – ❌ False (d) Human audible range is 20 Hz to 20,000 Hz. – ✅ True (e) Lower frequency means higher pitch. – ❌ False (f) Unpleasant sound is music. – ❌ False (g) Noise pollution may cause hearing loss. – ✅ True 4. Fill in the blanks ...

Conservation of Plants and Animals - Class 6 Q&A Class 8 Science - Conservation of Plants and Animals 1. Fill in the blanks with correct words. (a) What is the name of a place where animals are protected in their natural habitat? Wildlife sanctuary (b) What do we call species that are found only in a particular area? Endemic species (c) Why do migratory birds fly to faraway places? Climatic changes 2. Write the differences between the following. (a) What is the difference between a wildlife sanctuary and a biosphere reserve? Wildlife Sanctuary: Only animals are protected. Biosphere Reserve: Protects animals, plants, and nature. (b) How is a zoo different from a wildlife sanctuary? Zoo: Animals are kept in cages or artificial homes. Wildlife Sanctuary: Animals live freely in natural forests. (c) What is the difference between endangered and extinct species? ...

Class 8 Science - Friction Chapter Class 8 Science - Chapter: Friction 1. Fill in the blanks: (a) Friction opposes the motion between the surfaces in contact with each other. (b) Friction depends on the nature of surfaces. (c) Friction produces heat . (d) Sprinkling of powder on the carrom board reduces friction. (e) Sliding friction is less than the static friction. 2. Four children were asked to arrange forces due to rolling, static, and sliding frictions in decreasing order. Choose the correct arrangement. Answer: (c) static, sliding, rolling 3. Alida runs her toy car on different surfaces. The force of friction in increasing order will be: Answer: (c) towel, newspaper, dry marble floor, wet marble floor 4. Suppose your writing desk is tilted a little. A book on it starts sliding down. Show the direction of the frict...

Class 6 Science - Force and Pressure Class 8 Science - Force and Pressure 1. Give two examples each of situations in which you push or pull to change the state of motion of objects. Push examples: Pushing a swing to make it move back and forth. Pushing a trolley to start it moving. Pull examples: Pulling a door to open or close it. Pulling a toy car with a string to move it forward. 2. Give two examples of situations in which applied force causes a change in the shape of an object. Pressing a rubber ball changes its shape temporarily. Stretching a rubber band makes it longer and thinner. 3. Fill in the blanks in the following statements: (a) To draw water from a well we have to pull at the rope. (b) A charged body attracts an uncharged body towards it. (c) To move a lo...

Class 6 - Changes During Puberty: Q&A Class 6 - Changes During Puberty: Questions and Answers 1. What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body? The term is hormones . - Hormones are special chemicals made by endocrine glands. - They help control body changes like growth, mood, and puberty. 2. Define adolescence. Adolescence is the time when a child grows into an adult. - It starts after childhood and ends before adulthood. - Many physical and emotional changes happen during this time. 3. What is menstruation? Explain. Menstruation is the monthly shedding of blood and tissue from the uterus in girls. - It starts during puberty. - It means the body is getting ready for future baby-making. 4. List changes in the body that take place at puberty. - Boys grow facial and body hair. - Girls start menstruation. - ...

Class 6 - Reproduction in Animals (Q&A) Class 6 - Reproduction in Animals: Questions and Answers 1. Explain the importance of reproduction in organisms. Reproduction helps living things to continue their species. It produces new individuals and helps in the survival of the species. 2. Describe the process of fertilisation in human beings. Fertilisation happens when a male sperm joins with a female egg inside the female body, forming a zygote which grows into a baby. 3. Choose the most appropriate answer. (a) Internal fertilisation occurs (i) in female body ✅ (ii) outside female body (iii) in male body (iv) outside male body (b) A tadpole develops into an adult frog by the process of (i) fertilisation (ii) metamorphosis ✅ (iii) embedding (iv) budding (c) The number of nuclei present in a zygote is (i) none (ii) one (iii) two ✅ (iv) four 4. Indicate whether the followin...

Combustion and Flame - Class 6 Q&A Class 8 Science – Combustion and Flame 1. List conditions under which combustion can take place. Combustion needs fuel, oxygen, and heat. Without any one of these, burning will not happen. These are the three main things required. 2. Fill in the blanks: (a) Burning of wood and coal causes pollution of air. (b) A liquid fuel, used in homes is kerosene . (c) Fuel must be heated to its ignition temperature before it starts burning. (d) Fire produced by oil cannot be controlled by water . 3. Explain how the use of CNG in automobiles has reduced pollution in our cities. CNG burns cleanly and does not release harmful gases like petrol or diesel. It helps keep air clean in cities. 4. Compare LPG and wood as fuels. LPG is cleaner, burns faster and doesn’t produce smoke. Wood creates smoke and leaves ash. LPG is easier to store. 5. Give reasons: (a) Water conducts electricity....

Class 6 Science Q&A - Fossil Fuels and Petroleum Class 8 Science Questions and Answers 1. What are the advantages of using CNG and LPG as fuels? CNG and LPG are clean fuels. They do not pollute the air much. They are easy and safe to use. 2. Name the petroleum product used for surfacing of roads. Bitumen is used for surfacing roads. It is a thick black material obtained from petroleum. 3. Describe how coal is formed from dead vegetation. What is this process called? Coal forms from dead plants buried under the earth. Heat and pressure turn them into coal. This is called carbonisation. 4. Fill in the blanks: (a) Fossil fuels are coal , petroleum and natural gas . (b) Process of separation of different constituents from petroleum is called refining . (c) Least polluting fuel for vehicle is CNG . 5. Tick True/False against the following statements: (a) Fossil fuels can be made in the laboratory. – False (b...

Microorganisms: Friend and Foe - Exercises 1. Fill in the blanks (a) Microorganisms can be seen with the help of a microscope . (b) Blue green algae fix nitrogen directly from air and enhance fertility of soil. (c) Alcohol is produced with the help of yeast . (d) Cholera is caused by bacteria . 2. Tick the correct answer (a) Yeast is used in the production of (ii) alcohol (b) The following is an antibiotic (ii) Streptomycin (c) Carrier of malaria-causing protozoan is (i) female Anopheles mosquito (d) The most common carrier of communicable diseases is (ii) housefly (e) The bread or idli dough rises because of (iii) growth of yeast cells (f) The process of conversion of sugar into alcohol is called (iii) fermentation 3. Match the organisms in Column A with their action in Column B Bacteria - Producing antibodies Rhizobium - Fixing nitrogen Lactobacillus - Setting of curd Yeast - Baking of bread ...

Crop Production and Management - MCQ Answers Crop Production and Management - MCQ Answers (Class 6) 1. Select the correct word from the following list and fill in the blanks. float, water, crop, nutrients, preparation (a) The same kind of plants grown and cultivated on a large scale at a place is called __________ . ✅ Answer: A crop is a large number of the same kind of plants grown by farmers in one area to get food or other products. (b) The first step before growing crops is __________ of the soil. ✅ Answer: Preparation of soil means making the soil loose and fertile using tools so seeds can grow properly with air and water. (c) Damaged seeds would __________ on top of water. ✅ Answer: Damaged seeds float on water because they are empty inside or have air. Good seeds sink to the bottom. (d) For growing a crop, sufficient sunlight and __________ and __________ from the...

Class 7 Science Q&A Class 7 Science – Questions & Answers 1. Complete the journey of food through the alimentary canal by filling up the boxes with appropriate parts— Food → Mouth → ______ → ______ → Anus Food → Mouth → Oesophagus (food pipe) → Stomach → Intestines (small then large) → Anus. Food is chewed, pushed, churned, absorbed, then waste exits. 2. Sahil placed some pieces of chapati in test tube A. Neha placed chewed chapati in test tube B, and Santushti took boiled and mashed potato in test tube C. All of them added a few drops of iodine solution to their test tubes—A, B, and C, respectively. What would be their observations? Give reasons. • Test tube A: chapati turns deep blue-black; raw starch present. • Test tube B: little or no blue; saliva broke much starch. • Test tube C: darkest blue-black; boiled potato still rich in untou...

Science Questions and Answers — Earth, Moon and Sun Science Questions and Answers Earth, Moon and Sun Question 1 In Fig. 12.17, how many hours of Sunlight do the North Pole and the South Pole receive during one rotation of the Earth? Answer: During one rotation of the Earth (24 hours), both the North Pole and South Pole receive 24 hours of sunlight or 24 hours of darkness, depending on the season due to Earth's tilted axis. Question 2 — Fill in the blanks (i) Stars rise in the _______ and set in the _______. (ii) Day and night are caused by the Earth's _______. (iii) When the Moon fully covers the Sun from our view, it is called a _______ solar eclipse. Answer: (i) Stars rise in the east and set in the west. (ii) Day and night are caused by the Earth's rotation. (iii) When the Moon fully covers the Sun from our view, it is called a total solar eclipse. Question 3 — ...