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Chapter - 1 Chemical Reactions and Equations  INTEXT EXERCISE EXERCISE

CHAPTER – 2 MICROORGANISMS FRIEND AND FOR NCERT SOLUTIONS Question 1: Fill in the blanks:   (a) Microorganisms can be seen with the help of a microscope . (b) Blue green algae fix nitrogen directly from air to enhance fertility of soil. (c) Alcohol is produced with the help of yeast . (d) Cholera is caused by bacteria . Question 2: Tick the correct answer: (a) Yeast is used in the production of (i) sugar (ii) alcohol (iii) hydrochloric acid (iv) oxygen (b) The following is an antibiotic (i) sodium bicarbonate (ii) streptomycin (iii) alcohol (iv) yeast (c) Carrier of malaria-causing protozoan is (i) female Anopheles mosquito (ii) cockroach  (iii) housefly (iv) butterfly (d) The most common carrier of communicable diseases is (i) ant (ii) housefly (iii) dragonfly (iv) spider (e) The bread or idli dough rises because of (i) heat (ii) grinding (iii) growth of yeast cells (iv) kneading (f) The process of conversion of sugar into a

CHAPTER – 2 MICROORGANISMS FRIEND AND FOR REVISION NOTES Micro-organisms: Micro-organisms are too small and are not visible to the unaided eye. • They can survive under all types of environment, ranging from ice cold climate to hot springs and deserts to marshy lands. They are also found inside the bodies of animals including humans. • Micro-organisms are found in air, water and in the bodies of plants and animals. They may be unicellular or multicellular. • Micro-organisms are classified into four major groups. These groups are bacteria, fungi, protozoa and some algae. • Viruses are quite different from other micro-organisms. They reproduce only inside the host organism; bacterium, plant or animal cell. • Based on the significance, micro-organisms can be useful or harmful to us. Harmful effects of microorganisms: Bacteria: Causes various diseases such as typhoid, diarrhea, and cholera.  Fungi: Causes a large number of diseases in plants and

CHAPTER – 1 CROP PRODUCTION AND MANAGEMENT REVISION NOTES Crop: When plants of the same kind are grown and cultivated at one place on a large scale, it is called a crop. ➢ In India, crops can be broadly categorized into two types based on seasons - Rabi and Kharif crops. ➢ Sowing of seeds at appropriate depths and distances gives good yield. Good varieties of seeds are sown after selection of healthy seeds. Sowing is done by seed drills. ➢ Soil needs replenishment and enrichment through the use of organic manure and fertilizers. Use of chemical fertilizers has increased tremendously with the introduction of new crop varieties. ➢ The main tools used for tilling or ploughing are – Plough, Hoe, Cultivator Basic practices of crop production: (i) Preparation of Soil: One of the most important tasks in agriculture is to turn the soil and loosen it. The process of loosening and turning of the soil is called tilling or ploughing. (ii) Sowing: Sowing of seeds at

CHAPTER – 1 CROP PRODUCTION AND MANAGEMENT Question 1: Select the correct word from the following list and fill in the blanks.   float, water, crop, nutrients, preparation  (a) The same kind of plants grown and cultivated on a large scale at a place is called crop.  (b) The first step before growing crops is preparation of the soil. (c) Damaged seeds would float on top of water.  (d) For growing a crop, sufficient sunlight and water and nutrients from the soil are essential. Question 2: Match items in column A with those in column B. (i) Kharif crops - (e) Paddy and maize  (ii) Rabi crops - (d) Wheat, gram, pea  (iii) Chemical fertilizers - (b) Urea and super phosphate (iv) Organic manure - (c) Animal excreta, cow dung, urine and plant waste Question 3: Give two examples of each. (a) Kharif crop (b) Rabi crop  Answer:  (a) Kharif crop → Paddy, maize  (b) Rabi crop → Wheat, gram Question 4: Write a paragraph in your own words on each of the fol