Chapter: 1 The Human Body. Short answers

Transcription

1 Chapter: 1 The Human Body Class: 4th (B&G) Subject: Science Short answers 1. What is the main part of the body s nervous system? Ans: The Brain is the main part of the body s nervous system. 2. What does brain do? Ans : It controls speech,thought,balance,movement, the senses,,emotions, dreams and all other body functions. 3. Name the largest part of the brain? Ans: Cerebrum 4. What is the function of frontal lobe? Ans :It controls the reasoning,planning,emotions and problem solving. 5. Which part of the brain controls movement and balance? Ans : Cerebellum 6. What does the heart do? Ans: The heart pumps blood around the body. 7. Which gas is needed by humans to live and grow? Ans: All humans need oxygen to live and grow. 8. Name the parts of a human heart? Ans : The human heart is divided into four parts: 1. Right atrium 2. Right ventricle 3. Left atrium 4. Left ventricle 9. How does the oxygen rich blood flow in the heart? Ans : The oxygen rich blood flows from the left atrium into the left ventricle and then around the body. 10. How does blood without oxygen flow in the heart? Ans : The blood without oxygen flows from right atrium to the right ventricle then to the lungs. 11. Describe your intestines and explain the work they do? There are two intestines in our body. 1. Small intestine 2. Large intestine They help to digest food we eat and get rid of food that our body doesn t want.

2 LONG QUESTIONS Q1. What happens when you breathe in and out? Ans : a. Breathing in: When we breathe in, our lungs take in oxygen and they get bigger. This oxygen mixes with blood and pumps around our body. b. Breathing out: When we breathe out, we are getting rid of carbon dioxide that our body doesn t need. ** (Diagram is included) ** Q2. How do muscles work to bring about movement in your body? Ans: Muscles: Muscles are attached to the bones. Working: Muscles work by contraction and relaxing. Contracting means they get shorter. Relaxing means they get longer. In this way, they move the bones in the body. Chapter: 2 The Animal World Short Answers. 1. Name the essential things animals need to survive? Ans : All animals need three things to survive. a. Water b. Energy c. Oxygen 2. Why is there no life on other planets? Ans : There is no life on other planets because of absence of water. 3. What is water made from?write its chemical name? Ans : Water is made up of two chemicals Hydrogen (H) and Oxygen(O).The chemical name of water is H 2 O. 4. What is food chain? Ans : It shows us how energy is transferred through food. 5. What are carnivores, herbivores and omnivores? Ans : Carnivores : The animal that only eat meat e.g. cat, lion dog etc. Herbivores: The animals that only eat plants e.g.goat, horse, giraffe

3 Omnivores: The animals that eat both meat and plants e.g. humans, crows etc. 6. Define producers? Ans : Plants are known as producers because they can make their own food. 7. How is oxygen produced? Ans : Oxygen is produced by the plants. 8. What do animals give plants in return? Ans : Animals produce carbon dioxide for the plants. 9. Why do plants need carbon dioxide? Ans : Plants need carbon dioxide to make their food.(photosynthesis) 10. Why is movement important for animals? Ans : Animals move for many reasons a. Find food b. Find shelter c. Find water d. Escape predators 12.What is reproduction? Ans : The process by which living things produce new living things is called reproduction. 11. What are two ways of reproduction in animals? Ans : Sexual reproduction b. Asexual reproduction 12. Why is animal reproduction important? Ans : If living things didn t reproduce there would be no more living things. 13. What is metamorphosis? Ans : It is a process in which an animal changes its body structure during different stages of its life cycle. LONG QUESTIONS Q1. Explain food chain in detail? Ans : Food chain : The steps of food chain are given below. a. Producers: Plants use sunlight, water and minerals to make their own food.they are known as producers. B. Primary consumers: These consumers get their energy directly from the plants. E.g grasshopper C.Secondary consumers: These consumers get their energy by eating primary consumers.e.g shrew D.Tertiary consumers: These consumers get their energy by eating secondary consumers.e.g. owl

4 Q2. Discuss the life cycle of a frog. The life cycle of a frog is given below. a. Egg The female frog lays the egg in water. b. Tadpole: The eggs hatch into tadpole. c. Tadpole with legs: In this stage the tadpole has legs, has a longer body, a tail and a head. It breathes through gills. d. Frog let: The fog let breathes with lungs and still has some of its tail. e. Adult : The adult frog breathes with lungs and has no tail. (Diagram is included) Chapter 3: The plant world Short Answers 1. Name the main parts of a plant? Ans : There are FOUR main parts of a plant. 1. Root 2. Stem 3. Leaf 4. Flower 2. What is the function of roots? Ans : The roots absorb water and minerals from the ground. They also anchor the plant in the ground. 3. What is the job of the stem? Ans : It transports water up the plant. It also supports the leaves and flowers. 4. What is the function of leaves? Ans: The leaves produce food with the help of photosynthesis. 5. Why do leave look green? Ans: The leaves look most of the time because of chlorophyll. 6. What does chlorophyll do? Ans: The chlorophyll converts energy from the sun and when this is combine with water and carbon dioxide, food is produced. 7. How do we count the age of an old felled tree? Ans : We can do so by counting the old xylem rings in its trunk. 8. What is xylem and phloem?

5 Ans : The xylem and phloem are the plants tubes that transport water, minerals and glucose to all over the plant. 9. Name the important parts of a flower? Ans : A flower has four main parts. 1. Sepals 2. Petals 3. Stamen 4. Pistil 10. What are sepals and petals? What job they do? Ans : Sepals : The outer green coloured leaves in a flower are called sepals. They protect the bud. Petals : The petals are usually large and colourful.their job is to attract insects to the flower. 11. Name the male and female parts of a flower? Ans : Male part: Stamen (anther, filament) Female part: Pistil (stigma, style, ovary) LONG QUESTION Q1. Write a short note to explain the processes that need a plant to live, grow and reproduce? Ans :The four processes are : 1. Photosynthesis: Photosynthesis is the food producing process. This process takes place in leaves. 2. Transpiration: Transpiration takes place within the leaves. In this process, water evaporates from a plant. 3. Transportation: Plants have two types of tubes. a. Xylem b. phloem Xylem: they carry water and minerals from the roots the leaves. Phloem: they transport prepared food from the leaves to other parts of the plant. 4. Reproduction : In flowering plants, reproduction takes place in the flower. Some plants reproduce by growing new shoots.e.g strawberry plant.

6 Q2. How does fertilization take place in a plant? Draw a diagram to explain your answer. Ans : Fertilization: Plant fertilization takes place when bird, insect or the wind transfers pollen grains from the anther of one plant to the stigma of another plant. From stigma, the pollen goes down the style to the ovary, where it fertilizes an egg and a seed is formed. (Diagram is included) Chapter 4: Food and Diet Short answers 1. Name the components of a right food? Ans : A right food has following components: 1. Proteins 2. Carbohydrate 3. Minerals and vitamins 4. Fats and oils 2. What are muscles and organs made up of? Ans: Our muscles and organs are made up of protein. 3. Why does your body require protein? Ans : Protein helps our muscles and organs to grow and stay healthy. 4. What is protein made up of? Ans : Protein is made up of amino acids. 5. Name some protein rich food? Ans : Red meat, fish, poultry, eggs, beans, nuts, rice. 6. What are two types of carbohydrates? Ans : 1. Simple carbohydrates 2. Complex carbohydrates 7. Which carbohydrate is better to eat if you want lasting energy? Ans : Complex carbohydrates. 8. How do we obtain the minerals and vitamins we need? Ans : Minerals : Minerals come from the ground. They are absorbed by the plants and used by animals. Vitamins: Plants prepare all the vitamins by themselves while animals get their vitamins by eating plants and other animals. 9. Why does your body need minerals and vitamins? Ans : To fight against different diseases.

7 10. Enlist some minerals that are good for your body? Ans : 1. Calcium 2. Iron 3. Zinc 11. What is the difference between fats and oils? Ans : Fats are solid at room temperature while oils are liquid at room temperature. 12. Why are fats and oils good for your body? Ans : They are good for our nervous system,skin,protect vital organs and control our body temperature. 13. Which vitamins, minerals, oils or fats would you need to improve your.bones, immune system and skin? 1. Bones : Calcium, Vitamin D 2. Teeth : Calcium, Vitamin C 3. Immune system : Zinc 4. Skin : Vitamin A 14. What is a balanced diet? Ans : A balanced diet means eating the right variety of food in right amounts. 15. Name the components of a food pyramid? Ans : The food pyramid includes: 1. Cereals (roti, rice, bread etc) 2. Vegetables and fruits 3. Dairy products and meat 4. Sweets 16. What is meant by good hygiene? Ans : Good hygiene is about keeping clean. LONG QUESTIONS Q1. What are the food groups? Explain how each food group helps our body? Ans : The food groups are: 1. Proteins 2.carbohydrates 3. Minerals and vitamins 4. Fats and oils 1. Proteins : Proteins are body building food and repair our tissues and muscles. E.g meat, eggs, beans etc. 2. Carbohydrates: These are the quick source of energy.e.g. potatoes, carrots, rice etc. 2. Minerals and vitamins: They help our body to fight against different diseases.e.g milk, orange and meat etc. 3. Fats and oils: They are good for our nervous system, skin, protect vital organs and Control body temperature e.g. fish, nuts, olive oil etc.

8 Q2. Suggest any five ways to maintain good hygiene? Ans : Here are some ways to maintain good hygiene. 1. Clean your teeth twice a day. 2. Wash your body every day. 3. Change your clothes every day. 4. Wash your hair regularly. 5. Treat cuts and gazes when you get them as germs can get into your body and cause diseases. FINAL TERM CHAPTER: 8 FORCE, TOOLS AND MACHINES Short questions: 1. What is force? Ans : A force is push or pull. It makes things move. 2. What is buoyancy? Ans: It is an upward force that works in water. 3. Why do some things sink? Ans: Some things sink because their weight is more than the total weight of the water. 4. Why do some things float? Ans : Objects float because of buoyancy. 5. What is gravity? What effect does it have on objects? Ans : Gravity is a force that keeps us on the earth.it works because all objects pull other objects towards them. 6. Which thing keeps everything on the ground? Ans: Gravity keeps everything on the ground. 7. Why is it difficult to walk on a slippery floor? Ans : This is due to less friction. 8. What is a lever? Ans :A lever is a simple machine that can lift objects with little effort. 9. What is inclined plane? What it is used for? Ans: An inclined plane is a flat surface that joins one level with a higher level. It is used to move objects from lower level to an upper level. 10. What is wedge? Explain with the help of example? Ans :A wedge is two inclined planes joined together. It is used to split or cut things apart. Examples are chisel and axe.

9 11. How does a screw work? Ans :A screw is a plane wrapped around a cylinder. It is used to hold objects in place. 12. What type of simple machine is the door knob? Can you explain why? Ans : A door knob is a wheel and axle. Knob= wheel rest part= axle 13. Have you ever seen a crane lift a heavy load? What simple machine it is based on? Ans: A carne is a type of pulley. Long questions Q1. What is friction? Give two examples from daily life of how friction helps us. Ans : Friction : It is a force which slows down or stops the objects from moving. Examples: a. Friction appears when brake pads on a bike rub against the tyre to slow or stop the bike. b. A cricket ball rolls along grass and slowly stops due to friction. Q2. What is air resistance? Give two examples from daily life where its effect is used? Ans : Air resistance: It is a force which slows down the objects moving through air. Examples: a. It is harder to walk with the wind coming towards us due to air resistance. b. A parachutist falls slowly due to air friction. Chapter: 10 The Solar System Short questions: 1. What is the shape of earth? Ans: Our earth is sphere in shape. 4. In how much time the earth orbits around the sun? Ans : It takes the earth 365 days, 48 minutes and 46 seconds to orbit around the sun. 5. What is the axis of the earth? Ans : It is an imaginary line passing through the NORTH and SOUTH poles. 6. How do day and night occur? Ans : The spinning movement of the earth gives us night and day. 7. Why do people near the equator spin the fastest? Ans : This is because of the earth s shape and its spinning movement. 8. What is called a vacuum? Ans : A vacuum is an area that contains no matter. 9. Can we see nebulae from earth?

10 Ans: No, because they don t give out light. 10. Name the types of galaxies? Ans : Three types of galaxies are a. Spiral galaxies b. Elliptical galaxies c. Irregular galaxies 11. In which galaxy does our earth exist? Ans : Our earth exists in galaxy known as the Milky Way. LONG QUESTIONS Q1. How are the seasons caused? Explain with the help of a diagram. Ans : When the earth tilts on its axis, some parts of the earth are closer to the sun at certain times of the year, and further away at other times of the year. This is how we get the seasons. (Diagram is included) Q2. Write short notes on A. Space : Space is the area in which planets, stars, moons and other bodies are present. Space is a vacuum. It also has dust and gases. B. Nebulae: A nebula is a cloud of dust in space. Most of them contain a lot of hydrogen gas. Some nebulae are died stars. They don t give their own light. C. Galaxies: These are huge areas of space that contain stars, planets, dust and gas. There are three types of galaxies a. Spiral galaxies b. elliptical galaxies c. irregular galaxies Our earth and solar system are present in a galaxy known as the MILKY WAY.

11 Multiple choice questions Chapter : 8 force, tools and machines 1. Boats are able to float in water due to : a. Friction b. air resistance c. buoyancy d. gravity 2. has the most powerful force of gravity. a. The sun b. the earth c. the moon d. the solar system 3. Choose and circle two surfaces which provide greatest friction. a. Glass b. marble c. wood d. grass 4. Air resistance works when : a. Air speeds the object b. air slows the objects c. air twists the objects d. Air moves the object. 5. The arm of a lever is attached to a/an. a. Machine b. load d. fulcrum d. effort 6. Inclined planes are used to move objects: a. Up and down stairs b. from a rough to a smoother level c. from lower to a higher level d. none of the above 7. Which of the following is a wedge? a. Knife b. wheelbarrow c. saw d. chisel 8. Mark the statements that are not correct about a screw. a. it is used to hold objects in plane b. it is used to cut objects c. It is used to lift objects d. It is a type of plane 9. Which one of the following is an example of a wheel and axle? a. a cricket bat b. a skateboard c. a pair of scissors d. an axe 10. Inclined planes are useful for: a. lift weight b. easing the movement of the physically handicapped c. cutting cakes d. Growing crops

12 Chapter 10: The Solar System 1. A sphere is a solid : a. Rectangle b. circle c. Triangle d. oval 2. The revolving movement of the earth measures a a. Day b. month c. year d. none of these 3. The earth is continuously spinning on its:. a. Axis b. Poles c. orbits d. all of these 4. We get our because of the way the earth tilts. a. Weather b. seasons c. Rain d. storm 5. During their the earth s poles get no sunlight. a. Summer b. autumn c. winter d. spring 6. Space is a : a. Nebulae b. galaxy c. vacuum d. none of these 7. A nebula is a cloud of dust and. a. Solid b. liquid c. gas d. all of these 8. Most of nebulae contain a lot of : a. Hydrogen b. oxygen c. Carbon d. iron 9. Our earth exists in a galaxy known as. a. Black hole b. Milky Way c. ozone d. none of these 10.There are types of galaxies. a. One b. two c. three d. four