CBSE Class 10 Science 2017 · Paper 31(B)/C · Question 18

(i) The waste is separated on the basis of whether it can be broken down by biological processes (by decomposers such as bacteria and fungi). Biodegradable waste, such as fruit peels, fallen leaves, grass cuttings and left-over food, goes into one bin (usually the green one); non-biodegradable waste, such as polythene, plastic bottles, glass and metal cans, goes into the other (usually the blue one). (ii) Advantages: 1. The biodegradable waste can be composted into manure (or used for biogas), returning nutrients to the soil. 2. The non-biodegradable waste can be reused or recycled, so less of it stays in the soil and water or goes to landfills; and neither kind needs to be burnt, so no smoke or harmful gases are released into the air. (iii) Values shown by Praveen: concern for the environment, and a sense of responsibility as a citizen (civic sense), shown by guiding the other children; awareness of proper waste management.