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Lesson Understanding Rivers 4 Let Us Learn About R rivers and the parts of a river. U the important uses of rivers. A the pollution of rivers. h ways to reduce river pollution. Think Mr Irani’s school friend has come to visit the Irani family after many months. Meher: Hello, Ajay Uncle! How are you? Ajay Uncle: Hi, Meher. I am well. I have been very busy with work. Meher: Yes, I heard you telling Papa and Ma that you were doing some work to keep Mumbai’s rivers clean. What work do you do for the rivers? Ajay Uncle: Well, Meher, I work with an NGO that cleans Mumbai’s rivers. We organise events to pick up the waste thrown into rivers. We talk to school children about keeping rivers clean. We also speak to A polluted river the government to make cleanliness rules strict. It is very important to clean rivers because the health of our villages and cities depends on them. Meher: Oh! Are rivers really that important? NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 101 1 1/7/2019 2:57:11 PM

Q. Who is the responsible for keeping the rivers clean? (A)  children (B)  the government (C)  adults (D)  all of the above Remembering A river is a large natural stream of flowing water. Usually, rivers flow towards a large water body like a sea or ocean. Sometimes, rivers also flow into caves under the ground. Rivers provide water, which is necessary for all kinds of life forms. Various kinds of organisms live in rivers. Many kinds of plants and trees grow only near rivers. Also, many animals and insects get food and water from rivers. They are important for the growth of civilizations. Many important ancient cities started near rivers. A river begins on a high ground or in hills or mountains and flows down from the higher ground to the lower ground. It begins as a small stream and gets bigger as it flows onwards. The journey of a river is divided into high, middle and low areas. High Areas JOURNEY OF A RIVER Low Areas The place where a river Middle Areas The mouth of the river is begins is called its source. where it meets a large It is usually on high land. Here, the river slows down. water body such as a sea The water flows down The slope of the land is less. or an ocean. The mouth very fast. It carries rocks The river deposits sediments falls in the low areas. A and other materials along the middle course. river sometimes forms a with it. Sediments are the muddy delta at the mouth. and rocky materials brought source down by a river from the mountains or hills. slope flow of water A delta is a land made of the land sedimentary deposits left by of a river flowing into a large water body. A delta is usually a triangular piece of land. mouth (delta) 2 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 102

source mouth (delta) tributary distributary river bank A picture showing the course of a river Smaller streams When the main Soil brought down from the mountains and rivers from river breaks in the by a river is called silt. During the different places middle, different rainy season, rivers become full and which join the main streams are formed. flow over their banks. As a result, rivers are called These are called neighbouring areas get flooded. tributaries. distributaries. When the water from the flood flows away, mud or silt is left behind. Understanding USES OF RIVERS Some ways in which rivers are helpful to people are shown in the picture below. Let us discuss the uses in more detail. USES OF RIVERS Understanding Rivers 3 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 103 1/7/2019 2:57:11 PM

1) Agriculture: Silt brought from the mountains by rivers is very fertile. A riverboat It is very good for growing crops. Thus, it is helpful to farmers. Crops need water to grow. Rivers provide water for farming. The process A dam used to of supplying water from a river to the fields to grow crops is called generate electricity irrigation. This water is supplied in the required amount at regular gaps. Rafting on a river 2) Fishing: Rivers are a source of food such as fish, crabs, prawns and so on. These are sources of food for many humans and animals. 3) Transportation: Travelling by waterways is the cheapest form of transportation. Rivers provide a natural and easy way to travel or transport goods by boats and steamers. 4) Generating electricity: Several rivers move from high areas to middle areas. The force of water falling from a great height can be used to generate electricity. Dams help in holding water and generating electricity. 5) Recreation: People also use rivers for recreation. Some of these recreational activities are swimming, boating, fishing, birdwatching and so on. In the high areas, river rafting is popular. In the low areas, parasailing is popular. Application RIVER POLLUTION Unfortunately, nowadays, rivers are being polluted. Here are some reasons for river pollution. 1) Waste from farms, cities and factories is dumped in rivers. 2) People throw plastic into rivers. Fish, birds and other creatures eat this plastic and die. 3) After various festivals, people immerse idols of gods and goddesses into rivers. Very often, the paint used on these idols poisons underwater creatures. 4) Often, dead animals are also dumped in rivers. The water from polluted rivers can cause many diseases. The Ganga is one of the most polluted rivers in India. 4 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 104

Higher Order Thinking Skills (H.O.T.S.) WAYS TO REDUCE RIVER POLLUTION Look at the pictures of polluted rivers. Plan a presentation in groups of five to find ways by which rivers can be kept clean. Make sure the ways can be used by common people. Amazing Facts Given below are some important rivers of the world. 1) River Nile in Africa 2) River Yangtze in Asia 3) River Amazon in 4) River Danube in Europe South America The River Nile is around 6,690 km long. It is longer than the distance between Kashmir in the north and Kanyakumari in the south of India! Understanding Rivers 5 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 105 1/7/2019 2:57:11 PM

New Words 1) NGO – N on-Governmental Organisation; a group of people who want to help citizens without being a part of the government 2) civilization – a group of people who live together and share the same culture 3) river bank – the land along a river 4) recreation – things people do for fun 5) fertile – rich in nutrients to produce more crops 6) waterway – a river or a body of water that boats or ships use to go from one place to another 7) generate – make; produce 8) dam – a wall built across a river to store water 9) parasail – fly through the air wearing a parachute while being pulled by a boat 10) immerse – lower something in water 11) idol – a statue of a god or goddess 6 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 106

Lesson India’s Rivers 5 Let Us Learn About R the main rivers of India, their tributaries and distributaries. U the sources and features of the main rivers of India. A the main uses of Indian rivers. h u nderground rivers. Think Ajay Uncle: Which is the longest river in India? River Ganga Meher: Is it the river Ganga? Ajay Uncle: That is right! River Ganga is the longest river in India. It is 2,510 km long. The second-longest river is in the south of India — Godavari — which is 1,465 km long. Meher: Wow! That is really long! Q. Which is the longest river in India? (B)  Godavari (A) Narmada (D) Ganga (C) Brahmaputra NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 107 7 1/7/2019 2:57:11 PM

Remembering India has many rivers, big and small. Some of the important rivers of India are the following. • Indus • Ganga • Narmada • Tapi • Godavari • Krishna • Mahanadi • Brahmaputra All the major Indian rivers have their source at one of the following. 1) The Himalayan and the Karakoram mountain ranges in northern India: They have long courses and run from the source to the seas. These are called Himalayan rivers. Example: Indus, Ganga and Brahmaputra 2) The Vindhya and Satpura mountain ranges and Chota Nagpur Plateau in central India or the Sahyadri hills (Western Ghats) in western India: These are called peninsular rivers. Example: Mahanadi, Krishna, Kaveri and Godavari Indian rivers can also be divided according to their water levels. The Himalayan rivers have water throughout the year. Rivers that flow throughout the year are known as perennial rivers. Example: Ganga, Indus, Bramhaputra Many of the peninsular rivers do not have a constant flow of water all year. Rivers which do not have a constant flow throughout the year are known as non-perennial rivers. They have a seasonal or periodic flow of water. Example: Godavari, Mahanadi, Krishna Let us learn more about some rivers of India. HIMALAYAN RIVERS 1) Indus: It is one of the longest rivers in the world. Five major tributaries meet the Indus in Punjab (‘punj’ meaning ‘five’ and ‘ab’ meaning ‘water’). These are the Chenab, Jhelum, Ravi, Beas and Sutlej. 2) Ganga: It is the longest river in India. It meets the River Yamuna at Prayagraj (earlier called Allahabad). The Chambal and Betwa rivers are the tributaries of the Yamuna. The Son river is a tributary of the Ganga. The Hooghly river in West Bengal is a major distributary of the Ganga. 3) Brahmaputra: Beginning in Tibet, the Brahmaputra enters India in Arunachal Pradesh and flows through Assam. It then meets the Ganga in Bangladesh and flows into the Bay of Bengal. 8 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 108

PENINSULAR RIVERS 1) Mahanadi: The major tributaries of Mahanadi are Shivnath, Jonk and Hasdeo. It flows through the states of Chhattisgarh and Odisha. 2) Godavari: This is the second-longest river in India. Some tributaries of the Godavari are Pranhita and Indravati. It flows through Maharashtra, Madhya Pradesh, Karnataka, Odisha, Telangana and Andhra Pradesh. 3) Krishna: The Tungabhadra is the largest tributary of the Krishna river. The Krishna flows through the states of Maharashtra, Karnataka, Telangana and Andhra Pradesh. 4) Narmada and Tapi: These rivers flow from the east to the west. The Narmada and the Tapi flow through the states of Madhya Pradesh, Maharashtra and Gujarat. Rivers of India India’s Rivers 9 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 109 1/7/2019 2:57:11 PM

Understanding SOURCES OF INDIAN RIVERS The source of a river, very often, is in the mountains or hills. Mountain range like the Himalayas and Karakoram are very high. They have snow on their peaks. This snow melts in summer and trickles down the mountainsides in small streams. These streams flow into rivers. Such rivers are called snow-fed rivers. When rivers are formed due to the melting of glaciers, they are called glacier-fed rivers. The rivers of central and southern India are mostly rain-fed rivers. This means that they receive water from the monsoon rains. Snow or glacier-fed rivers of northern India Rain-fed rivers of central and southern India • perennial rivers • seasonal rivers — they lose a lot of water during summer • flow slowly when they reach the plains • flow faster than rivers of northern India due to rocky and uneven land • few waterfalls (A waterfall is formed when • many waterfalls water falls from a great height.) Example: Jog Falls in Karnataka FEATURES OF INDIAN RIVERS 1) In the high areas, a river flows fast. It rubs against rocks and breaks them into smaller pieces. It carries these small rocks and stones as well as soil down along with it. 2) A river leaves small rocks and stones as well as soil at the bottom of valleys or takes them down to the plains. 3) These rivers also form large basins. A river basin is the area which gets water and silt from the main river High areas of the Ganga and its tributaries. This is how the Ganga makes the plains very fertile for cultivation. 4) The rain-fed eastern peninsular rivers such as Mahanadi, Krishna and Godavari, flow towards the east like the Ganga. They deposit silt in the middle and low areas. Deltas form at their mouths. These rivers flow into the Bay of Bengal. 5) Some of the main rain-fed peninsular rivers like Narmada, Periyar and Tapi, flow towards 10 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 110

the west. They flow faster than the northern rivers and do not deposit as much silt in their middle and low areas. They do not form deltas. These rivers flow into the Arabian Sea. Application IMPORTANT USES OF INDIAN RIVERS Some important uses of Indian rivers are as follows. 1) Agriculture • R ivers carry soil rich in nutrients (silt). Silt that is carried by the Ganga, Yamuna, Godavari and so on is useful for agriculture. • The large basins and deltas of the rivers provide a lot of fertile land for farming. • River water is diverted through canals to areas where there is no water. 2) Electricity • The Sardar Sarovar Dam on the Narmada river is an example of a dam built to generate hydroelectricity. 3) Religion • Many rivers in India are considered sacred. Many religious events are performed on the banks of these rivers. 4) Fishing • Fishing is done in the Hooghly river in West Bengal. Similarly, many other Indian rivers are the source of fish for Indians. 5) Transportation • S ome waterways are used for transportation. Example: the Ganga-Bhagirathi-Hooghly rivers flowing from Uttar Pradesh to West Bengal, the Bramhaputra river in Assam 6) Recreation • Rishikesh, on the banks of the Ganga, is a famous spot for river rafting. Higher Order Thinking Skills (H.O.T.S.) underground RIVERS Sometimes, in the middle areas, a river might disappear from the surface of the Earth. This does not always mean that it has dried up. Sometimes, a river finds a crack in the ground and begins to travel under the ground. India’s Rivers 11 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 111 1/7/2019 2:57:11 PM

A few underground rivers from around the world are the Neglinnaya in Moscow and the Fleet in London. Amazing Facts The Sunderban delta formed by the Brahmaputra and the Ganga is the largest delta in the world. It is one of the most fertile areas in the world. New Words 1) Western Ghats – mountains in the western part of India 2) canal – a river made by humans 12 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 112

Lesson Natural Resources: 6 Forests Let Us Learn About R forests as a natural resource. U the features of different types of forests found in India. A causes and effects of deforestation. h c onservation of forests. Think Rashi is excited. A student from Chikkamagaluru, Karnataka is visiting her school. Her name is Maya. Rashi: Maya, are you impressed with the buildings in the city? Maya: Well, they are not as impressive as what we have in Chikkamagaluru. Rashi: Really? What do you have in Chikkamagaluru? Maya: We have the Western Ghats. Kudremukh National Park, which is close to my place, is a UNESCO world heritage site. See how gorgeous it is! Maya shows Rashi some pictures. Kudremukh National Park Rashi: Wow! It is beautiful! Maya: You must visit me there! It is in an evergreen forest. Q. Which forest-rich state is Maya from? (A) Tamil Nadu (B) Karnataka (C) Maharashtra (D) Rajasthan NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 113 13 1/7/2019 2:57:11 PM

Remembering Forests as a natural resource A forest is an area covered with many trees and plants growing close to each other. Most forests grow naturally, that is, on their own. They are a home for a wide variety of animals and birds. A natural resource is anything that people can use which comes from nature. People do not make these resources but they use them. Example: air, water, wood, oil, iron, coal. Forests are one such important natural resource. Let us look at some things we get from forests. Things we get from forests Understanding Not all forests are the same. There are many different kinds of forests. They have various types of trees and plants. The five main types of forests found in India are as follows. 14 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 114 1/7/2019 2:57:11 PM

1) 2) 3) Coniferous forests Evergreen forests Deciduous forests 4) 5) Thorny and scrub forests Tidal forests CONIFEROUS FORESTS • Location: Coniferous forests are found in regions such as the The tall and pointed trees of Himalayan and Nilgiri mountains. These regions are quite coniferous forests cold. It also snows on the Himalayas. • Features: The trees are pointed and narrow at the top and wider at the bottom. This prevents snow from remaining on their branches. The leaves are like needles so they do not collect snow. • Example: pine, cedar EVERGREEN FORESTS • Location: Evergreen forests are found in hot and wet regions of India. There is plenty of rain and sunshine on the Western Ghats, the hills of north-eastern India and on the Andaman and Nicobar Islands. • Features: These trees never shed their leaves completely and always look green. Hence, they are called evergreen forests. An evergreen forest Natural Resources: Forests 15 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 115 1/7/2019 2:57:11 PM

• Example: eucalyptus, rosewood DECIDUOUS FORESTS • Location: These forests grow in the Peninsular Plateau region A deciduous forest in of India. They are also found along the foothills of the summer the Himalayas. • Features: The trees in these forests live and grow in different kinds of weather. These trees have broad, flat leaves. They require lots of water. Hence, they lose their leaves during the dry season. • Example: gulmohar, teak THORNY AND SCRUB FORESTS • Location: Thorny and scrub forests are found in hot and dry An arid scrub forest areas. These include the deserts of Rajasthan and Gujarat, parts of Uttar Pradesh, Madhya Pradesh and Maharashtra. • Features: The rays of the Sun are very strong in these regions. There is very little rainfall. So, the trees and plants need to live with less water. They have leaves that have become thorns to make sure they do not lose water. Their roots are long because they have to penetrate deep into the soil to search for water. • Example: babul, keekar TIDAL FORESTS • Location: These forests are found where the land is flooded A tidal forest by sea water such as the river deltas of West Bengal. • Features: The roots of these trees grow upwards to come out of the water. They do this to get enough air. • Example: sundari, keora WHAT AFFECTS THE VEGETATION OF A PLACE? Factors such as temperature and rainfall of a region will determine the type of forest found there. • Since tall mountains in India are extremely cold, coniferous forests are found there. 16 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 116 1/7/2019 2:57:11 PM

• Hot climate and heavy rainfall lead to evergreen forests. • Scanty rainfall and high temperature make thorny and scrub forests grow in the desert. cold Grass Coniferous forests TEMPERATURE Deciduous forests hot 1) Evergreen forest 1 2) Tidal forest 3) Thorny and scrub forest 23 a lot of rainfall RAIN very little rainfall Factors affecting the vegetation of a place Application What will happen if forests are destroyed? We have learned how forests are useful to people in many ways. Deforestation occurs when trees of a forested area of land are cut down but not replanted. This can have seriously bad effects on the environment. Why does deforestation occur? 1) Forests are cleared so that the land can be used for farms, buildings, roads and factories. 2) Trees from forests are used as raw materials to make products such as paper and rubber. 3) Forests are cut down for mining. When natural resources found under the Earth's surface, such as coal or minerals, are dug and brought out of the ground, it is called mining. Natural Resources: Forests 17 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 117 1/7/2019 2:57:11 PM

What are the effects of deforestation? If forests are destroyed, all life forms on  Earth will be harmed. Let us read about some effects of deforestation. 1) Plants absorb carbon dioxide and give out oxygen. Destroying the forests changes the climate of that region. 2) The roots of trees hold soil firmly together. So, when it rains, the soil can quickly soak in all the water. But deforestation makes the soil loose, and when there is heavy rain, the water flows away quickly, carrying the top Deforestation layer of the soil. This causes soil erosion. In mountainous areas, deforestation leads to landslides. 3) Deforestation disrupts the water cycle. So, there is less rainfall and the water bodies dry up. Higher Order Thinking Skills (H.O.T.S.) Now that we have understood the harmful effects of deforestation, let us see how we can stop it. There are two ways to do this. REFORESTATION Reforestation means to plant trees again in an area where there was a forest earlier. It can also refer to planting trees in a place where the number of trees are decreasing. There are areas where trees have been cut down and the land is not used. We can plant trees there. AFFORESTATION Some places have land but no forests. Afforestation is the process of planting trees in a barren land without any trees to create a forest. 1) Ask your teachers, parents and grandparents the following questions. a) Do they remember parts of your town or city that used to be forests? b) Which animals lived there? 18 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 118 1/7/2019 2:57:11 PM

Amazing Facts Some trees can live for thousands of years and grow to become more than hundred metres tall. The Hyperion, found in Northern California, is the tallest tree in the world, measuring nearly 116 m. It is as tall as a 30-storey building! New Words 1) UNESCO – United Nations Educational, Scientific and Cultural Organization 2) spice 3) prevent – the thing that we use to add different flavours to food 4) foothills – stop something from happening 5) penetrate – the smaller hills found near tall mountains 6) raw material – go into something with force and effort 7) soak – the resources used to make something – make something wet with water Natural Resources: Forests 19 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 119 1/7/2019 2:57:11 PM

Lesson Natural Resources: Soil 7 Let Us Learn About R d efinition of soil, layers of soil and types of soil found in India. U e ffects of soil on plant and animal life; soil erosion. A why we should preserve and protect soil. h m aking a mind map on how soil helps us. Think Rashi: Maya, what makes a forest grow? Why do some forests have very tall trees and other forests have shorter trees? Maya: See, like there are different kinds of forests, there are different kinds of soil too. The type of trees in a forest depends on the kind of soil found there. Rashi: How does this happen? A plant growing in soil Maya: There are many reasons why soil varies in different parts of the country. Q. What causes different types of forests to grow in different places? (A)  different soils (B)  different people (C)  different states (D)  different animals 20 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 120

Remembering We have learned that forests are one of the key natural resources. Another very important natural resource is soil. It is important for life on Earth. Soil is the upper layer of earth in which plants grow. It is a mixture of various materials such as humus, clay and rock particles. Soil can be used for the following. Soil used for farming Soil used for making bricks Soil used to make pots LAYERS OF SOIL Soil is made up of many layers. Let us see them in the diagram. Topsoil (made up of vegetation and is rich in humus) Subsoil (made up of clay, sand, silt and minerals) Broken down fragments (made up of rock fragments, little clay and minerals) Parent rock (rocks that break down to form soil) Layers of soil Natural Resources: Soil 21 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 121 1/7/2019 2:57:11 PM

TYPES OF SOIL IN INDIA There are six types of soil found in India. Let us find out more about these types of soil by using the two symbols given below. Where are they found?  W hat crops are grown in each type of soil? 22 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 122

Mountain soil Alluvial soil Red soil Black soil Laterite soil Arid soil Major soil types in India 23 Natural Resources: Soil 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 123

Understanding We now know about the different types of soil. Let us see how soil affects plant and animal life. Living beings depend, directly or indirectly, on soil. SOIL EROSION We learned how important soil is for plant and animal life. So, we need to protect our soil from soil erosion. Soil erosion is the washing (by water) or blowing away (by wind) of the top soil on the surface of the Earth. How can we preserve and protect soil? 1) P lant more trees. This is especially helpful in places where the soil is exposed to wind and flowing water. Planting trees creates a speed-breaker in the path of fast blowing winds across flat lands. These plants and trees can stop the wind from carrying the soil away. 2) S top cutting trees. Trees and plants keep soil in place when water flows swiftly. The soil gets caught in the roots of the bushes rather than being washed away. 24 1/7/2019 2:57:11 PM NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 124

Application Why should we preserve and protect soil? • M icroorganisms of different types live in soil. Each microorganism helps plants and other living things in its own special way. • The soil stores gases like carbon dioxide. During soil erosion, these gases are released into the air. These gases are often harmful to living things. Some gases such as nitrogen also help plants grow well. These need to be present in the soil. • Soil, especially topsoil, is an important natural resource especially for farmers. When the topsoil is carried away, it affects crops. Crops do not grow well in areas were topsoil is lost. • It can take approximately 100 years to form one inch of soil. This means that once topsoil is eroded, it cannot be replaced quickly. Higher Order Thinking Skills (H.O.T.S.) 1) Make a mind map to show the following. a) the things people get directly from soil b) occupations which depend on soil Amazing Facts There are more than 7,000,000,000 (7 billion) people on the entire Earth. In any handful of Earth, there can be up to 50,000,000,000 (50 billion) microorganisms. This means that there can be more microorganisms in a few handfuls of earth than people on Earth! New Words 1) humus – part of soil made up of decomposed plant and animal remains 2) microorganism – a living thing that can only be seen with a microscope 3) exposed – left open Natural Resources: Soil 25 NR_BGM_9789386663351 MAPLE G04 INTEGRATED TEXTBOOK TERM 2_Text.pdf 125 1/7/2019 2:57:11 PM

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