Current Affairs 4th Class

                                                                          Plants   The leaves of most of the plants contain a green colored pigment called chlorophyll. Green leaves are responsible for making food. Thus, they are also known as food factories of the plants. Plants uses carbon dioxide, sunlight and water for making food. Upper surface of a leaf has more chlorophyll for trapping the sunlight. On the undersurface of the leaf, there are tiny pores known as stomata which can only be seen through microscope. The stomata are responsible for exchange of gases in plants. Water and essential minerals are absorbed by the roots of the plant from soil and then it is transported to leaves through stem. On the undersurface of leaves, there are fine network of lines called veins. Main vein is located at the center of the leaf called midrib. Main vein has two tubes. One tube carries water and minerals from the stem to the leaf. The other one takes food from the leaf to other parts of the plant. A leaf is attached to the stem by a stalk. Leaves Photosynthesis The process of making food by plants in the presence of sunlight, water, carbon dioxide aid chlorophyll is called photosynthesis. During photosynthesis, plants take carbon dioxide and release oxygen. Food is prepared by plants in the form of glucose. Plants store extra food in fruits and seeds as starch. Trees store food in their trunks in the form of cellulose. Cactus do not have leaves. Photosynthesis occurs in their stems.   Cactus Some plants are not green. For example, mushroom. Another plant like croton plant has red coloured leaves. The red colour of the leaves is due to the presence of anthocyanin. But they have chlorophyll also. Photosynthesis takes place in these plants also. Croton Mushrooms do not have chlorophyll. They cannot make their food from photosynthesis. They get food from dead plants and animals.   Classification of Plants Plants are of various types classified on the basis of where they grow.   Terrestrial Plants Plant that grows on land are called terrestrial plants. They are further divided into various types such as: Mango tree Plants in hilly areas In hilly areas, plants can make food easily as there is sufficient sunlight and rainfall in these places. Coniferous tree grows on hills and mountains. They have standing branches so that snow which falls on them gets down. Conifers are generally evergreen as they do not shed their leaves. They do not produce flowers. Their leaves have few stomata only. Coniferous tree Desert plants Plants that grow in hot places like deserts are called desert plants. Their leaves are modified into spines. Instead of leaves, food is prepared in stems. more...

                                                                              Animals   Living things can move, eat food and produce young ones. The process of producing young ones is called reproduction. Different animals reproduce by different methods. Some animals lay eggs and some give birth to young ones.   Egg Laying Animals Animals like birds, reptiles, insects and amphibians lay eggs. An egg is an organic vessel in which an embryo begins to develop.   Birds Birds lay eggs. Eggs have a hard, protective shell. Which contains a yellow yolk surrounded by white albumen. The yolk provides food to the chick growing inside it. The growing chick is called embryo. The parent bird sits on the egg to keep it warm. The chick breaks the shell and comes out when it has grown. This is called hatching.   Insects Insects reproduce by laying eggs. Insects like butterfly and housefly have four stages in their life cycle i.e. egg, larva, pupa and adult. The egg is hatched into a larva. The young one looks different from the adult. The larva of a butterfly is known as caterpillar and that of a housefly is called a maggot. The larva first grows rapidly by eating the leaves. Then after sometime, it stops eating and forms a covering around itself called as cocoon. This is called the pupa. The larva changes into an adult inside the pupa and comes out of it after sometime.     Amphibians Amphibians reproduce by laying eggs in water. The young frog which comes out of the egg is known as tadpole.   Fishes Fishes also reproduce by laying thousands of eggs in water. But only few eggs grow into baby fishes. Fishes   Reptiles Reptiles lay eggs in the sand or rotting vegetation. They do not sit on the eggs to keep them warm. The sea makes them warm and the egg is hatched. Animals Gluing Birth to Young Ones Mammals are the animals which give birth to young ones and produce milk to feed them. They do not lay eggs. Dogs, monkeys, cats and human beings comes under the category of mammals. Bats are flying mammals. Whales and dolphins are also mammals living in water.   Habitat The home or natural environment of a living thing is known as habitat. All living beings changes themselves to survive in the natural world, for example, birds and insects can fly. This is called adaptation.   Classification of Animals on the Basis of Their Habitat Animals are classified on the basis of the place where they live.   Aquatic Animals Animals which live in water are called aquatic animals. Fishes live in water. They have fins for swimming in water. They have gills for breathing. Aquatic animals like dolphins and whales do not have gills. They have lungs for breathing for which they have to come to the surface of water. Birds like ducks have webbed feet which more...

                                                            Functioning of Human Body   All human beings require energy for doing various kinds of activities. They get this energy from food that they eat. The food we eat cannot be used by our body directly. It has to be broken down into a simpler form. Our body has a system for breaking down the food into a simpler form. This system is called digestive system.   Digestive System The process of digestion takes place in the following steps:
  • First we eat food which goes into the mouth. Our mouth has teeth for chewing and cutting the food into smaller pieces. Thus, the process of digestion begins in the mouth.
  • In the mouth, a digestive liquid called saliva mixes with food to make it a fine paste. Saliva breaks down food into starch and soluble sugar.
  • Food then passes into the stomach through the food pipe. The stomach is a hollow, muscular bag-like structure. In the stomach, the food again mixes with some more digestive juices for further break down into simpler form.
  • From the stomach, the food passes into long coiled tube called the small intestine its wall produces more digestive juices.
  • Liver and pancreas also pour their juices into the small intestine. These juices help to digest the food completely.
  • Digested food is then absorbed by a network of blood vessels present in the small intestine. The absorbed food is then carried to different parts of the body.
  • Small intestine is not able to digest water and roughage. Therefore, they are passed into the large intestine. The blood in the walls of the large intestine absorbs the water and carries it to the kidneys.
  • The semi-solid waste is then thrown out from the body through the anus.
      Digestive System of Human Body   Parts of Teeth A tooth has three parts. Crown, neck and root. Crown: Crown is that part of tooth that we can see. Neck: Neck is below the crown. Root: through roots, tooth is fixed in the jaw. The gum covers the root.   The outer hard layer which covers the tooth is called enamel. Enamel is the hardest thing in a human body. Dentine is below it. The core of the tooth is called pulp. Pulp is soft and has blood vessels and nerves in it. The nerves are connected to the gum through a hole in the root.   Types of Teeth There are four kinds of teeth in our mouth which are as follows:   Incisors The teeth which have sharp straight edges are called incisors. These are four in number in each jaw. They are present in front of the jaw. They help to cut or bite the food. Canines Canines are located on either side more...

                                                                        Measurement   We need to measure many different things in our daily life like length of objects, height, weight (of fruits, vegetables, etc.) amount of milk, water and so on.   Measurement of Length In early days, people used body parts to measure lengths.             Cubit                    Hand span   The metre is what we normally use for measuring lengths. Smaller lengths are measured in centimetres. Metre is written as m and centimetre as cm.   Measurement of Mass Mass tells us how heavy or light an object is. We use weighing scales to find the mass of an object. Just as we use metre for measuring length, we use kilogram for measuring mass. Smaller weights are measured in grams. Kilogram is written as kg and gram is written as g.   Measurement of Capacity Capacity of a container is the amount of liquid it can hold. Litre is the commonly used unit for measuring capacity. Smaller units are measured in milliliters. Liter is written as / and milliliters as ml.   Some Other Units of Measurement In everyday life, we also need to measure things that do not involve length, mass, and capacity. Time and temperature are two such examples. Time is measured in seconds. Measure of hotness or coldness of an object is called temperature. Temperature can be measured with the help of a thermometer  

                                                                   Matter and Materials   Matter Anything that occupies space and has mass is called matter. Everything around us is made up of matter. matter is made up of atoms. Water bottle, school bag, rubber, pencil are all made up of matter.   States of Matter Matter exists in three forms - solid, liquid and gas. Matter can change from one form to another on heating and cooling.   A solid can change into a liquid. This will happen if you heat the solid. The solid will melt into a liquid. This process is called melting. If you continue to heat the liquid will change into a gas. This is called evaporation. If you fill water in an ice tray and keep it in the freezer, you will see that after some time the liquid water has turned into ice. We say that the water has frozen and the process is called freezing. When a gas cools it change into the liquid state we say that it has condensed. And, the process is called condensation. The formation of rain in the water cycle is a natural example of the change of state of matter.   Changes Around Us Matter is constantly changing around us. Changes are of two types - physical changes and chemical changes. In physical change, no new substance is formed. Breaking or glass, melting of ice into water are some, examples of physical change. When ice melts the solid water turned to liquid water. It doesn't turn into food or cold drink or anything new. It remains water. Physical changes can be reversed. In a chemical change, new substance is formed. Changing of milk into curd is an example of chemical change. Similarly burning of paper, making of vegetable dishes from raw vegetables, bursting of crackers are some other examples of chemical changes. Unlike physical changes, chemical changes cannot be reversed.   Rocks Our earth is made up of rocks. Rocks are hard stones. Pebbles are small pieces of rock. Rocks are useful to us in many ways. Rocks such as marble, granite and sandstone are used in making buildings. World's seventh wonder Taj Mahal is made up of white marble.   Soil Formation
  • Soil formation starts when rocks break down into smaller pieces due to wind, rain and the sun's heat. These smaller pieces mix with dead and decaying animals and plants to form soil.
  • It takes thousands of years to form a small amount of soil.
  • Different types of soil contain different types of particles. These particles differ in colour and softness.
  • Soil contains pebbles, gravel, clay, humus, water and air. The water trapped in soil is called moisture.
  • Soil provides a bed for both animal and plant life.
  • We get many useful minerals such as diamond, granite, marble, and ruby from
  • Remains of living things found deep under layers of rocks are called fossils.
  Minerals Minerals more...

                                                              Force, Work and Energy   Whenever we push or pull an object, we apply force. A force can make an object move, can stop a moving object, can change direction of a moving object and can change the shape of an object.   Types of Force There are different types of forces:   Muscular Force It is the force exerted by muscles of our body. For example, lifting a bucket, lifting dumbbells, etc.   A man lifting a dumbbells   Elastic Force It is the force exerted when an elastic material is stretched. For example, stretching of rubber band. Stretching of a rubber band   Frictional Force It is the force exerted by two surfaces on each other in opposite direction when one moves over the other, while they are in contact. For example, while walking on a road frictional force is acting between the road and the sole of our shoe. Friction, between shoes and floor   Gravitational Force The force exerted by the centre of the earth which pulls objects towards it. For example, when a ball is thrown in the air, it comes back towards the earth due to gravitational force, an apple falling from a tree, etc. Falling of an apple due to gravitational force   Electrostatic Force When we rub a comb through dry hair, the comb gets charged and is able to attract tiny bits paper. The force exerted by charged comb on the bits of paper is called electrostatic force.   Charged hairs exert force on balloon   Work Work refers to an activity that involves applying force on an object and movement of the object in the direction of the force. For example, if a man lifts a bucket then some work is done. In this case, due to the force applied by the man, the movement of bucket takes place in upward direction.   Simple Machines The tools which make our work easy are called simple machines. For example, pulley, wheel and axle, lever, inclined plane, etc.                                      Pulley                             Inclined plane Energy Energy is the capacity or ability to do work. Energy can be of various types.   Mechanical Energy This is the energy of motion that does some work. For example, wind turns a windmill. Heat Energy Heat energy is produced when a fuel is burnt in the air. For example, when coal is burnt in the air, heat energy is produced. Heat energy is used in steam engines, in cooking, etc. Atomic Energy The energy obtained by splitting more...

                                                             Our Environment   Our Environment is composed of physical and biological things surrounding us. It has physical or abiotic factor and biological or biotic factor. Physical components includes soil, air, water, minerals and other nonliving things around us. Biological components includes plants, animals and micro- organisms.   Pollution Pollution is the undesirable change in the physical, chemical and biological constituents of our surroundings. Pollution is of various types:   Air Pollution Air pollution occurs when the air contains dust particles, gases, fumes in that amount which is harmful for us. The substances causing air pollution are called air pollutants. Industries and vehicles discharge harmful gases into the air making it dirty and unfit for breathing. Sun has ultraviolet rays which are absorbed by ozone layer present in the atmosphere. These rays can cause skin cancer. Due to air pollution ozone layer is getting depleted.   Effects of Air Pollution Air pollution has various effects which are explained below.   Breathing Problem When we inhale polluted air, it causes breathing problems. Bronchitis and asthma are diseases caused by air pollution.   Global Warming Human inhales oxygen and gives out carbon dioxide, when amount of carbon dioxide increases in air, it causes global warming. Global warming is the heating up of atmosphere due to excessive amount of carbon dioxide in the air.   Acid Rain Sometimes harmful gases discharged by factories and vehicles mixes with water vapours in the clouds. When it rains, these harmful gases get mixed with water vapours and comes down as acid rain. It affects forests, soil and human health. It makes soil more acidic. It also damages buildings, monuments etc.   Water Pollution When toxic substances enter lakes, rivers, oceans and other water bodies, it causes water pollution. There are many sources of water pollution. Sewage from cities is thrown into water resources without treatment. Polluted water causes diseases like jaundice, typhoid, diarrhea etc.    Factories discharges harmful chemicals directly into water which causes damage to aquatic plants and animals.   Soil Pollution Land gets polluted when we dump garbage on it.   Wastes are of two types: Biodegradable: Things like fruits, vegetable peels/ paper etc. get decayed by microorganisms and mixes with soil.   Non-biodegradable: Things like plastic, polythene which do not get decayed by microorganisms and remains as it is in the soil and pollute the soil.      

                                                                    Our Universe   Our Universe Our universe consists of number of stars, planets including our earth and moons.   Solar System       The sun and the eight planets belong to a family called solar system. The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. All of them revolve in fixed path called orbit. Planets rotate on their axis also. Most planets have their satellites which revolve around them. Satellite does not have its own light. Man has also made some satellites for weather forecasting and to help in communication which are known as artificial satellites, for example, Aryabhata, Rohini etc.   Stars and Planets A star is a huge ball of hot gases. It gives out heat and light. Planets do not have any heat or light of their own. They appear bright because they reflect the light of the stars. They revolve around stars. The sun is actually a star because it has its own heat and light. It is a huge sphere of hot gases. The earth and other seven planets that revolve around the sun get heat and light from the sun. The sun is the main source of energy in our solar system. The planet Mercury is closest of the sun, followed by Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. They revolve around the sun in fixed path called orbit. Stars are far apart from each other. Distance between stars is measured in light years. The distance travelled by light in one Year is called light year. The planets also rotate on their axis. Most of the planets have satellites. A satellite is a heavenly body that revolves around planets. It does not have any light of its own. The moon is a natural satellite of the Earth. It shines as it reflects sunlight from its surface. The moon does not have an atmosphere to protect it from extreme heat or cold. Some satellites in the sky are artificial. They have been sent up by scientists of different countries to study space, to forecast weather or to help in communication. The first one of these was Sputnik 1. Some others are Aryabhata, Rohini, INSAT, etc.  

Analogy   Learning Objectives
  • To get aware of analogy.
  • Increasing interest about this segment of reasoning.
  • Improving the general awareness.
  • Increasing the word power.
  Introduction Analogy means ‘Co-relation’. In other words, it is the way of establishing relation between two different objects, on the basis of some common features. Analogy may be of different types, which are discussed in this chapter.   (i) Profession In these types of questions, two words are given. These words are related to each other in profession. Given below are the examples of analogy based on profession.
  • Farmer: Field
  • Warrior: Battlefield
  • Engineer: Site
  • Sailor: Ship
  • Pilot: Cockpit
  • Beautician: Parlour
  • Artist: Theatre
  • Actor: Stage
  • Chef: Kitchen
  • Lawyer: Court
  • Scientist: Laboratory
  • Teacher: School
  • Doctor: Hospital
  • Clerk: Office
  • Servant: House
  • Driver: Cabin
  • Grocer: Shop
  • Painter: Gallery
  • Waiter: Restaurant
  • Worker: Factory
  • Umpire: Pitch
  • Gambler: Casino
  •   Analysis
    • Chef: Kitchen, Chef works in a kitchen.
    • Farmer: Field, Farmer works in a field.
    • Warrior: Battlefield, Warrior fights in a battlefield.
    • Engineer: Site, Engineer works on a site.
      Commonly Asked Question   1.            Doctor is related to Patient in the same way Lawyer is related to . (a) Customer                  (b) Accused (c) Magistrate                 (d) Client (e) Doctor   Answer (d) is correct. Explanation: Lawyer is related to Client.   2.          Chef is related to Restaurant in the same way Druggist is related to . (a) Medicine                   (b) Pharmacy (c) Store                        (d) Chemist (e) Restaurant   Answer (b) is correct Explanation: Druggist is related to Pharmacy.     (ii)     Dwelling Place In this type of questions, words are related to each other as per their dwelling. For example:
  • Bird: Nest
  • Cattle: Barn, shed
  • Dog: Kennel
  • Chicken: Coop
  • Pig: Sty
  • Sheep: Fold
  • Spider: Web
  • Squirrel: Drey
  •   Analysis
    • Rabbit: Burrow, Rabbit lives in burrow.
    • Dog: Kennel, Dog lives in Kennel.
    • Horse: Stable, Horse lives in Stable.
    • Tiger: Lair, Tiger lives in lair.
      Commonly Asked Question   1.          Fish: ? (a) Stable                       (b) Den (c) Aquarium                  (d) Aviary (e) Kennel Answer (c) is correct. Explanation: Fish lives in Aquarium.     2.             Monk: ? (a) Monastery                 (b) Den (c) Aquarium                  (d) Aviary (e) Kennel Answer (a) is correct. Explanation: Monk lives in Monastery.   (iii)      Quality In this type of questions, words are related to each other on the basis of their quality. For example:
  • Farmer: Crop
  • Hunter: Prey
  • Carpenter: Furniture
  • Author: Book
  • Goldsmith: Ornaments
  • Butcher: Meat
  • Cobbler: Shoes
  • Poet: Poem
  • Dramatist: Play Ballet
  • Architect: Design
  • Chef: Food
  • Producer: Film
  •   Analysis
    • Producer: Film, Producer produces the film.
    • Judge: Judgement, Judge gives the judgment.
    • Teacher: Teaching, Teacher teaches the student.
    • Editor: Editing, Editor edits the newspaper.
      Commonly Asked Question   1.            more...

    Classification   Learning Objectives
    • To get aware of classification.
    • Increasing interest about this segment of reasoning.
    • Improving the general awareness for solving problems.
    • Increasing the word power for solving problems.
        What is Classification? You must have in your mind what classification means. In fact, in classification, we take an element out of some given elements and the element to be taken out is different from the rest of the elements in terms of common properties, shapes, sizes, types, nature, colours, traits etc. In this way the remaining elements form a group and the element that has been taken out is not the member of that group, as this single element does not possess the common quality possessed by rest of the elements. For example, if we compare the animals like, lion, cow, tiger, panther, bear and wolf, then we find that this is a group of animals. How do we classify then? To understand this let us see the presentation given below:     Here, if we want to separate out one animal then definitely that animal will be cow because cow is the only animal in the group which is a domestic animal. Rest of the animals (lion, tiger, panther, bear and wolf) are wild animals. Hence, rest of the animals (lion, tiger, panther, bear & wolf) form a group of wild animals separating out the domestic animal (cow). Similarly, out of 6 letters A, M, N ,W, P and Q, we will take out A and form a group of 5 letters M, N, W, P & Q because out of given six letters only A is a vowel while remaining letters form a group of consonants.   Types of Classification   (i)     Letter Based Classification Such classification is based on letters of English alphabet. Many groups of letters are given in the question in which one group is different from remaining group and hence, the different group will be our answer.   Example 1.            Find the odd one out of the following options. (a) P Q T                       (b) U V Y (c) D E H                       (d) U N (e) F G J   Explanation:   (a)                       (b) (c)                        (d)   (e)     It is clear that except option (d), all the other options have a gap of 2 letters between 2nd and 3rd letter and the 1st two letters are in consecutive order. While in case of option (d), 1st two letters are in consecutive order but there is a gap of 3 letters between 2nd and 3rd letter. This is the reason why option (d) separates itself out of the remaining options. Hence, more...

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