Microbes such as. Lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and convert it into curd. During growth, such bacteria produce adds (mainly lactic add) that coagulate and partially digest the milk proteins. A small amount of curd, known as starter, is added to the milk and kept at a suitable temperature, where lactic acid bacteria multiply in millions and converts milk into curd that also improves its nutritional quality by increasing vitamin BI2. It also checks the growth of disease-causing microbes in the stomach.So, the correct answer is '(i), (ii) and (iii)'