(i) Section 2.4 of the chapter states that microorganisms are found everywhere—in water, soil, air, and even inside our bodies. The chapter specifically mentions in Section 2.4 that bacteria live in our gut and help in digestion, as also studied in Grade 7 chapter 'Life Processes in Animals'. (ii) Activity 2.8 explains that yeast is a type of microorganism belonging to the fungi group. During respiration, yeast breaks down food and releases carbon dioxide gas, which forms bubbles that make the dough soft and fluffy. This property is used in making breads, cakes, and pastries. (iii) Section 2.4.2 describes that Rhizobium bacteria form nodules in the roots of legumes like beans, peas, and lentils. These bacteria trap nitrogen from the air and make it useful for plants, helping them grow better without chemical fertilisers.