Microorganisms Friend And Foe Notes

Friend and foe Class 8 NCERT Notes. Humans are multicellular organisms made up of several trillions of cells grouped into specific cells as well as organs. Write a short paragraph on the harms caused by microorganisms. Crop Production and Management Agriculture,Crop Protection,Harvest and Storage 14. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation. Bacteria- Microorganisms : Friend and foe Class 8 NCERT Notes. The entire NCERT textbook questions have been solved by best teachers for you. Watch World of Microorganisms explained in the form of a story in high quality animated videos. Diseases- causing Microorganisms in plants. Most microorganisms are beneficial, for example, there are microorganisms in our large intestine that synthesise vitamins and allow them to be absorbed into the bloodstream. Fill in the blanks: a) Microorganisms can be seen with the help of a__. Normal flora must be considered when examining cultures for a suspected pathogen. All notes listed below are linked to Word documents (. they are also enemies because there are some microorganisms which cause simple diseases like cold and fever & also serious diseases likecholera and typhoid by bacteria,measles and chicken pox by viruses and. A group of similar microorganisms living together is called Ans. Immunology, from its earliest inception, has been concerned with biological identity—its establishment and maintenance. parvula) and foe (S. Fungi are larger. Chapter 2 Microorganisms: Friend and Foe. This is a key part of what is know as the interactome. Lactobacillus is an example of bacteria. Microorganisms – Friend and Foe Notes for Class 8, CBSE By Team Sarthaks on February 22, 2019 Important topics covered From Microorganisms – Friend and Foe Chapter: Introduction to microorganisms Commercial and Medicinal use of Microorganisms Harmful microorganisms Food poisoning Food preservation…. Some microorganisms spoil food, clothing and leather. Role of Autophagy in Proteostasis: Friend and Foe in Cardiac Diseases. Microorganisms are used for the preparation of curd, bread, cake, and alcohol. Microorganisms are too small and are not visible with the naked eye. It needs to cover all syllabuses in a simple manner. A microorganism, or microbe, is a microscopic organism, which may exist in its single-celled form or in a colony of cells. A table summarizing the disease characteristics of the major milk pathogens is presented at the beginning of this section, followed by a more detailed discussion of the microorganisms in milk, listed in alphabetical order: Brucella spp. 5 Food Preservation 2. I refer you study material from following sites. Extramarks offers NCERT solutions for Combustion & Flame of CBSE Class 8. MICRO ORGANISMS - FRIEND AND FOE - PART I | Microorganisms -bacteria, fungi,protozoa and some algae. In a forgotten and ruined land, a strange golden dust transforms a free-spirited bird into a lost child, setting off a chain of events that will reshape the world in unexpected ways. CBSE worksheets for Microorganisms: Friend and Foe worksheet for class 8 in PDF for free download. Human-Microbe Interaction Chapter 28 Microbes; Friend and Foe Microbes normally grow on and in the bodies of higher organisms. Facts about microorganisms. They may be considered M1, also known as classical or pro-inflammatory, and M2 also known as alternative macrophages, but with intermediate states of activation (19, 20). Effects of bacteria on their human host The genomes and the respective proteomes of microbes in the body frequently interact with those expressed by their human hosts. CBSE NCERT Solutions For Class 8 Science Chapter 2. Chapter 2 Class 8 - Microorganisms : Friend and Foe; Concepts. Find out more about how microbes play a key role in maintaining life on Earth, including fixing gases and breaking down dead plant and animal matter into simpler substances that are used at the beginning of the food chain. Microorganisms are present all around us but they are too small to be seen with naked eye. Friction between the paper and the pen enables us to write. Yeast is used as a raising agent in baking. Microorganisms friends and foe Worksheet-2. Anthrax is a dangerous human and cattle disease caused by a bacterium. In this article I would also explain about various types of bacteria, fungi, algae, protozoa and viruses. Normal flora must be considered when examining cultures for a suspected pathogen. There are different groups of microorganisms, that is, bacteria, fungi, protozoa and viruses. Microorganisms Friend and Foe. Nutrition 6. Some of the common. Website for CBSE Notes Class 10 and 12. The study of microorganisms is known as microbiology. Distribution 4. The entire NCERT textbook questions have been solved by best teachers for you. Friendly Microorganism Notes PPT Video. Yeast is a microscopic fungus that grows on plant sugars. Some microorganisms decompose the organic waste and dead plants and animals into simple substances and reduce pollution. Weakend or killed microbes 3. Chapter wise Study notes for Class VIII cbse students. Class 8 Science Notes Chapter 2 Micro-organisms : Friend and Foe PDF Free Download. NCERT Solutions Class 8 Science Chapter 2 Microorganisms Friend and Foe PDF Free Download. Microorganisms Friend and Foe is a chapter in CBSE Standard 8th Science Textbook. CBSE Syllabus For Class 8 Science: Although schools affiliated to the Central Board of Secondary Education (CBSE) conduct their own annual exams for Class 8, the syllabus is the one recommended by CBSE - the NCERT curriculum. In chapter 2 of class 8 science, you will study about them in detail. In a forgotten and ruined land, a strange golden dust transforms a free-spirited bird into a lost child, setting off a chain of events that will reshape the world in unexpected ways. They can repeat the lessons as many times as required. Watch World of Microorganisms explained in the form of a story in high quality animated videos. NCERT syllabus for chapter"Microorganisms: friend and foe:, class 8 is followed. Preservation of foods by fermentation is a widely practiced and ancient technology. More than 3885 downloads this month. Friend and foe Class 8 NCERT Notes. Neither your address nor the recipient's. After reading this article we will have a basic idea about:- 1. Microorganisms like amoeba can live alone, while fungi and bacteria may live in colonies. Bacteria are larger. Buy Print Copy of this Book Printed Study Material for IAS Exam (UPSC Pre Cum Mains Combo) Get Gist of NCERT Books Study Kit for UPSC Exams Go Back To NCERT Books Main Page. Unified council NSTSE conducts examination for classes 2 to 10. Class VIII Science Solutions NCERT. Beneficial yeast is pure and carefull. all are caused by microorganisms. They help us in many things like making curd. Evernote stores your notes locally and online. Some common human diseases caused by microorganisms. 0 Notes - Microorganism-Friend and Fo. Some microbes are even found in extremely harsh conditions, e. They are present everywhere in the atmosphere(air, water and soil) INTRODUCTION 3. Assignments, Notes, Sample Papers, Chapter test and other study material will be uploaded very soon. They can live in all kinds of environment, ranging from ice cold climate to hot springs, deserts and marshy lands. In a forgotten and ruined land, a strange golden dust transforms a free-spirited bird into a lost child, setting off a chain of events that will reshape the world in unexpected ways. The way the topics are covered form an important impression of the subject on the mind of the students. Bacteria like blue green algae, rhizobium increases the fertility of the soil. 0 and Version 10. Microorganisms cause diseases in human beings, plants and animals. Microorganisms are the organisms, which are very small and cannot be seen, except with the help of microscope. Classification 7. In jams and jellies sugar reduces _____ content which inhibits the growth of bacteria. University) and has many. Inquiry / Feedback Form; Student Helpline; Formula Book; Glossary; Chapter-2 Microorganisms : Friend and Foe / अध्याय. Biology Notes for UPSC IAS Prelims (Part I) - Biology is one of the disciplines of science under which, we study about the various aspects of living organisms. Where do Microorganisms Live?Microorganisms may be single-celledlike bacteria, some algae and protozoa,or multicellular, such as algae and fungi. *FREE* shipping on qualifying offers. TOPICS: - Friction, Microorganisms: Friend and Foe Q1. 13 class clips. They are even found inside and on our body. Viruses are quite different from other microorganisms. This learning module is totally based on latest Science Textbook of CBSE Board. The atmospheric nitrogen cannot be taken directly by plants and animals. 2 MICRO-ORGANISMS: FRIEND AND FOE (PASTE THIS PAPER IN YOUR BIOLOGY NOTE BOOK AND LEARN THEM THOROUGHLY. 3 Microorganisms and Us 2. The NCERT solutions for class 8 Science provided here are helpful for the students to clear all their doubts in the chapter in an easy and interesting way. University) and has many years of experience. Microorganisms friends and foe Worksheet-2. NCERT Science Class 8 Chapter 2 - Microorganisms: Friends and Foe September 17, 2009 Write a short note on 'Nitrogen Fixation'. CBSE notes followed by NCERT includes food preservation, useful and harmful microorganisms. Here we have given NCERT Class 8 Science Notes Chapter 2 Microorganisms: Friend and Foe. Microorganisms: Friends and Foe (Practice Sheet, Class 8) Pollution of Air and Water (Practice Sheet, Class 8) Reaching the Age of Adolescence (Parctice Sheet, Class 8) Reproduction in Animals(Practice Sheet, Class 8) Some Natural Phenomena (Practice Sheet, Class 8) Sound (Pratice Sheet, Class 8) Stars and the Solar System (Practice Sheet, Class 8). 1-2 μ m, average 1 μ m (micrometer) 2. They all have their own characteristics. Click here for quiz on Microorganism -Friend or Foe […]. Some of the common communicable diseases caused by microorganisms affecting humans are cholera, common cold, chicken pox and tuberculosis. Bacteria like blue green algae, rhizobium increases the fertility of the soil. Microorganisms are present all around us but they are too small to be seen with naked eye. Bacteria like blue green algae, rhizobium increases the fertility of the soil. Detailed Solutions for maths Chapter 6 Detailed Solutions for Solutions for NCERT Class 6 Mathematics Handwritten notes for Class. CBSE Notes and Study Materials for Science class 8 Chapter Chapter 2. Ans: Microorganisms can be very harmful to us, as they cause a number of human and animal diseases. Chapter 2 Microorganisms: Friend and Foe. VIII Microorganisms-Friend and Foe Solved Questions Read Download CBSE 8th science: "Notes ands Questions Answers" Read Download. Microbes - friend or foe? This free course is available to start right now. Bacteria are larger. Microorganism: Friend And Foe. NCERT Class 8 Science Solutions for Chapter 2. Fill in the blanks: Note to our visitors :-Thanks for visiting our website. So, read a brief detailed description about microorganisms and increase your general knowledge. Bacteria- Microorganisms : Friend and foe Class 8 NCERT Notes. The main microorganisms in and on our bodies are protozoa, algae, fungi, bacteria and viruses. Buy Print Copy of this Book Printed Study Material for IAS Exam (UPSC Pre Cum Mains Combo) Get Gist of NCERT Books Study Kit for UPSC Exams Go Back To NCERT Books Main Page. In this article I would also explain about various types of bacteria, fungi, algae, protozoa and viruses. Download complete NCERT book for Class VIII, in Science subject. You might have watched advertisements on television saying tap water is unsafe, or use aqua-guard, a water purifying system in order to get water safe for drinking. Commercial use of micro organism - Yeast is used in the formation of alcohol and wine. Microorganisms are too small and are not visible with the naked eye. 1 November Update October 17, 2017 During the weekend of November 18, 2017, Fannie Mae will update Desktop Underwriter® (DU®) Version 10. However, a tiny minority are pathogens (disease-causing agents). CBSE Study is a another web portal of ATP Education. made by Gaurav pareek. NCERT Solutions for Class 8 Science PDF free download, NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe, to Study online or download free in PDF form. Microorganisms : Friend or Foe. Given their warm and humid environment, washrooms provide an ideal setting for the survival of microorganisms. Crop Production and Management Agriculture,Crop Protection,Harvest and Storage 14. List of Topics in "Microorganisms: Friend and Foe" Microorganisms. 1 Microorganisms 2. Which provides online study materials for cbse students, teachers and tutors only, It also provides, cbse notes, sample papers, solved sample papers, NCERT solutions, practise papers, previous years papers, textbook solutions. Neither your address nor the recipient's. Microbes' role in Baking. Eubacteria (Bacteria) prokaryotic cell type 1. Fill in the blanks. Benefits of Visiting A Physiotherapist. CBSE Class 8 Science Notes Chapter 2 Microorganisms: Friend and Foe. Download Simple Sticky Notes latest version 2019. Unified council NSTSE conducts examination for classes 2 to 10. Anthrax is a dangerous human and cattle disease caused by a bacterium. Here we have provided NCERT Exemplar Problems Solutions along with NCERT Exemplar Problems Class 8. 1 to include the change described below. A Poison Tree Questions and Answers - Discover the eNotes. Some microbes are even found in extremely harsh conditions, e. Answer: Although microorganisms are useful but there are some microorganisms which are harmful for us. In a forgotten and ruined land, a strange golden dust transforms a free-spirited bird into a lost child, setting off a chain of events that will reshape the world in unexpected ways. Toppers practice daily and use QuizNext to practice from 100,000+ questions for FREE. Diseases in humans like common cold, tuberculosis, measles, chicken pox, polio, cholera, typhoid, hepatitis-B, malaria etc. Microorganisms: (i) Organisms which are too small to be seen by the naked eye, especially a single celled organism is called microorganisms or microbes. Revision Quizzes, Videos, Worksheets, Test Papers and more. Come meet the good, the bad, and the ugly―yes, germs!. Practice CBSE online Guess Questions (Quiz) for all subjects. Macrophage Polarization. Use this drawing of a paramecium to answer the next two questions: 2. So, read a brief detailed description about microorganisms and increase your general knowledge. 3 Microorganisms and Us 2. 2 MICRO-ORGANISMS: FRIEND AND FOE (PASTE THIS PAPER IN YOUR BIOLOGY NOTE BOOK AND LEARN THEM THOROUGHLY. Class 8 Important Questions for Science – Microorganisms : Friend and Foe NCERT Exemplar Class 8 Science is very important resource for students preparing for VIII Board Examination. Class VIII Science Solutions NCERT. Explain nitrogen cycle. They reproduce only inside the host organism; bacterium, plant or animal cell. The NCERT solutions for class 8 Science provided here are helpful for the students to clear all their doubts in the chapter in an easy and interesting way. Shapes: coccus (spherical or round) pairs – diplococcus. CBSE- Microorganisms - Friend and Foe Notes Microorganisms- A living organism that is very minute to be seen by the naked eye, especially a single celled organism, such as a bacterium is called microorganism. CBSE Notes for Class 8 science in english medium and other notes for class 06, class 07, class 08, class 09, class 10, class 11, class 12. Common ailments like cold, influenza (flu) and most coughs are caused by viruses. ppt), PDF File (. Microorganisms are present all around us but they are too small to be seen with naked eye. This is a syllabus outline for Class 8 for NSTSE Examination 2019. CBSE Class 8 Science Notes Chapter 2 Microorganisms: Friend and Foe. Get Revision notes of Class 8 th Science Chapter 2 Microorganisms : friend and foe to score good marks in your Exams. contraptions, etc, instant personal loan bad credit and achieving your, most severe foe? Unless/ until, a friend or relative thinks, before you go, everything that Short Term Personal Loans she needs, ways is it possible, to understand, so. Classification 7. It is due to the action of yeast that the dough rises, if you leave it for sometime adding yeast to it during kneading. Nail is fixed in the wall due to friction. When I first looked at Google Keep I blushed, taken aback by the beauty of its design. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from 6th century BC India and the 1st century BC book On Agriculture by Marcus Terentius Varro. parvula) and foe (S. Friction between the match stick and the side surface of it, helps us to light a match stick. Download CBSE Revision Notes for CBSE Class 08 Science Microorganisms Friend And Foe in PDF format. 5 August 29, 2019. We show you how to backup and restore your Evernote notes. Yeast is a microscopic fungus that grows on plant sugars. Weakend or killed microbes 3. Here we have given NCERT Class 8 Science Notes Chapter 2 Microorganisms: Friend and Foe. Microorganisms cause diseases in human beings, plants and animals. NCERT Solutions for Class 8 Science PDF free download, NCERT Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe, to Study online or download free in PDF form. Inflammation: Both friend and foe Click here to read Dr Arien's article in Destiny Magazine As foe, the common denominator present in all chronic degenerative diseases The word ‘Inflammation’ comes from the Latin word ‘inflamatio’, which means to inflame, to set on fire. ppt), PDF File (. Graphing Quadrants. Assignments, Notes, Sample Papers, Chapter test and other study material will be uploaded very soon. Some of the microorganisms cause diseases in human beings, plants and animals. They are found everywhere on the earth in air, water and land. In lieu, have the vendor to modify about the ignition and then permit van idle. Joan Huntley. They reproduce only inside the host organism; bacterium, plant or animal cell. A vaccine Contains And. Our notes of Chapter 1 to 18 are prepared by Maths experts in an easy to remember format, covering all syllabus of CBSE, KVPY, NTSE, Olympiads, NCERT & other Competitive Exams. CBSE Ncert Notes for Class 8 Biology Microorganisms: Friend and Foe. NCERT Solution for Class 8 Science - Chapter 2 (Microorganisms Friend and Foe) Question 1. They help us in many things like making curd. In this activity you will use MULTIPLE websites to try to identify some of the microorganisms you are observing in your sample of pond wate. Welcome to Friend & Foe, an indie game developer based in Tokyo. Fungi are larger. This portal is designed to support Students and Teachers of Central Board of Secondary Education. lesson plan : Waste water story. CBSE Class Notes Online - Classnotes123. Classification 7. They reproduce only inside the host organism; bacterium, plant or animal cell. Microorganisms range in complexity from single to multicellular organisms. Our atmosphere has 78% nitrogen gas. Microorganisms cause diseases in human beings, plants and animals. CBSE Syllabus for Class 8 All Subjects. Desktop Underwriter/Desktop Originator Release Notes DU Version 10. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation. Here, we present Fill in the blanks quiz questions to learn on Microorganisms Friend and Foe. This really is an illustration which the vehicle was in fact involved in an car crash plus a invest in to not complete. Virus reproduce only inside the cells of the host organism, which may be a bacterium, plant or animal. Microorganisms are too small and are not visible with the naked eye. Friendly Microorganisms Making curd - Lacto bacillus is a bacterium that promotes the formation of curds Bacteria are also involved in making of cheese. They are about the same size. Get Revision notes of Class 8th Science Chapter 1 to 18 to score good marks in your Exams. Biology L2- Microorganisms: Friend and Foe. These microorganisms or microbes are so small in size that they cannot be seen with the unaided eye. Meaning of Microorganisms 2. This is a key part of what is know as the interactome. In its given premises, biology includes a wide. 13 class clips. CBSE NCERT Solutions For Class 8 Science Chapter 2. In a forgotten and ruined land, a strange golden dust transforms a free-spirited bird into a lost child, setting off a chain of events that will reshape the world in unexpected ways. This learning module is totally based on latest Science Textbook of CBSE Board. Each question carries 1mark. In its given premises, biology includes a wide. in the crater of volcano and in sulphur springs. Three key characteristics—individuality, immunity, and identification—together have defined immune identity, and as one notion changes meaning, so do the others. Investigation of microorganisms is accomplished by observ-. Such disease-causing microorganisms are called pathogens. NCERT Solution for Class 8 Science - Chapter 2 (Microorganisms Friend and Foe) Question 1. Get Revision notes of Class 8 th Science Chapter 2 Microorganisms : friend and foe to score good marks in your Exams. Key Notes Material downloaded from and Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks Chapter - 2 Microorganisms: Friend and Foe • Microorganisms: Microorganisms are too small and are not visible to the unaided eye. Please note that these NCERT solutions are designed and written by experts in the industry so that students also get to learn the Maths tricks if that can be applied to a particular question. It did want I wanted. Author information: (1)Department of Microbiology, University College, Cork, Ireland. Microorganisms, CBSE Science Class 8 Chapter Wise Solved Q&A. For example, we might have observed that during rainy season moist bread gets spoilt and its surface gets covered with greyish white patches. Discover (and save!) your own Pins on Pinterest. Normal flora must be considered when examining cultures for a suspected pathogen. Answer 8: Microorganisms are harmful in many ways. A Poison Tree Questions and Answers - Discover the eNotes. Microorganisms: Friend and Foe World of Micro Organisms, Dealing with Harmful Micro Organisms, Food Preservation, Nitrogen Fixation 15. A Poison Tree Questions and Answers - Discover the eNotes. There are many reasons to visit a physiotherapist. Microorganisms: Friend and Foe. Given their warm and humid environment, washrooms provide an ideal setting for the survival of microorganisms. Chapter wise Study notes for Class VIII cbse students. Disease in plants reduces the yield of crops. Video: Friend or foe? Fun facts about sharks. Visit the post for more. Answer 8: Microorganisms are harmful in many ways. The antibiotics are manufactured by growing specific microorganisms and are used to cure a variety of diseases. One Word Answers 1. 2 Where do Microorganisms Live? 2. Download NCERT solution of 8th Science NOW! As per NCERT language with colored diagrams. CHAPTER - 2 : MICROORGANISMS : FRIEND AND FOE CHAPTER - 3 : SYNTHETIC FIBRES AND PLASTICS CHAPTER - 4 : MATERIALS : METALS AND NON-METALS CHAPTER - 5 : COAL AND PETROLEUM. 1 Microorganisms 2. What are microbes? There are some living organisms which are all around us but we cannot see with eyes alone. Friction between the match stick and the side surface of it, helps us to light a match stick. It didn’t crash and. Chambers, Markus J. Fill in the blanks. (ii) Microorganisms are classified into four major groups- bacteria, fungi, protozoa and some algae. • Father of Microbiology-Louis Pasteur. This learning module is totally based on latest Science Textbook of CBSE Board. Class 8 Science Notes Chapter 2 Micro-organisms : Friend and Foe PDF Free Download. Its a fun way of learning using assessments. Microorganisms - friend and foe notes for class 8 is here. 2 Where do Microorganisms Live? 2. Sebaceous glands are microscopic exocrine glands in the skin that secrete an oily or waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals. A group of similar microorganisms living together is called Ans. This PPT contains all the chemistry formulas for class 9 as well as the periodic table. 4 Harmful Microorganisms 2. txt) or view presentation slides online. In _____ the milk is heated to about 70ºC for 15 to 30 seconds and then suddenly chilled and stored. Note: Discovery Education is a free site with great resources for teachers. MICROORGANISMS : FRIEND AND FOE. List of Topics in “Microorganisms: Friend and Foe” Microorganisms. Some of the microorganisms cause diseases in human beings, plants and animals. • Father of Microbiology-Louis Pasteur. Topic,Revision Notes and 2 Test. made by Gaurav pareek. Micro-organisms and their habitat. Class 8 Microorganisms Friend And Foe Short Answer Questions 1. Microorganisms are present all around us but they are too small to be seen with naked eye. microorganisms: friend and foe class 8(vishakha) 1. Microorganisms : Friend and Fo. The deal is still going through the regulatory processes. Microorganisms. Learn Science with Notes and NCERT Solutions Class 6 Class 7 Class 8 Class 9 Class 10. CLASS 8 SCIENCE CHAPTER 2 MICROORGANISMS: FRIEND AND FOE QUESTION ANSWERS, Name the microorganisms which can fix atmospheric nitrogen in the soil. CBSE Study is a another web portal of ATP Education. Title: microorganisms friend and foe 1 Microorganisms Friend and foe. Visit the post for more. Quick Notes: SOAP Notes EMR software for Patient Reports and Patient Notes is both easy and educational to use with the latest technoligy like iPads, Pads, tablets, portable wireless, paperless, barcode readers and touchscreens. These cbse revision notes are arranged subject-wise and topic-wise. Nomenclature – scientific name binomial system of Linnaeus Genus species ex. CBSE/NCERT (III-X), online practice test on CBSE/NCERT (III-X),CBSE,Class-VIII,Science,Microorganisms: Friend and Foe We will be performing routine server maintenance on Oct 16 between 11:30 pm to 01:00 am IST. Posted by Jsunil at 9:00 AM. CBSE NCERT Solutions for Class 8th Science Chapter 2 : Microorganisms : Friend and Foe. Micro-organisms and their habitat. Some of the common. Find out more about how microbes play a key role in maintaining life on Earth, including fixing gases and breaking down dead plant and animal matter into simpler substances that are used at the beginning of the food chain. Free Subject Notes for Maths, Science, English. Hernando De Soto. This PPT will make reading more enjoyable and students will be able to memorize all the formulas very quickly. Definition of friend or foe in the Idioms Dictionary. Microorganisms are too small and are not visible with the naked eye. microorganisms See more. Conservation of Plants and Animals, Cell- Structure and Functions Rational Numbers, Linear Equations in One Variable, Quadrilaterals, Data Handling. Chapter 1: Crop Production and Management Chapter 2: Microorganisms: Friend and Foe Chapter 3: Synthetic Fibres and. Blue green algae fix nitrogen directly from air to enhance fertility of soil. Microorganisms: Friends and Foe (Practice Sheet, Class 8) Pollution of Air and Water (Practice Sheet, Class 8) Reaching the Age of Adolescence (Parctice Sheet, Class 8) Reproduction in Animals(Practice Sheet, Class 8) Some Natural Phenomena (Practice Sheet, Class 8) Sound (Pratice Sheet, Class 8) Stars and the Solar System (Practice Sheet, Class 8).