Urban Waste Disposal

The governing concept is source segregation, in which different kinds of waste are separated before collection and treatment. Wet or biodegradable waste can be sent for composting or other biological treatment, while dry materials such as paper, glass, metal, and some plastics can be sorted and recycled. This improves the quality of recyclable material, lowers contamination, supports safer handling, and reduces the amount sent to landfills. Therefore, option A is correct: separate bins make recycling easier and more effective. Option B is the opposite of the intended result. Options C and D are not necessary consequences of segregation; proper separation generally helps reduce pollution and pressure on natural resources.

The governing concept is composting, a biological method of managing organic waste. In this process, microorganisms decompose materials such as vegetable peels, food scraps, leaves, and garden waste under suitable conditions of moisture, air, and temperature. The decomposed material becomes compost, which can be used as an organic manure or soil conditioner. Therefore, option A is correct. Recycling generally means processing used materials such as paper, glass, metal, or plastic into usable products; it is not the specific term for making manure from biodegradable waste. Desalination removes salts from water, while mining extracts minerals from the Earth, so options C and D are unrelated.

The governing concept is composting, a biological method of managing biodegradable waste. Materials such as dry leaves, vegetable peels, grass, and food leftovers are placed under conditions where microorganisms decompose them. With suitable moisture, air, and time, the material changes into a dark, relatively stable substance rich in organic matter, commonly used as compost or manure to improve soil structure. Therefore option B is correct. Evaporation changes liquid water into vapour, mining extracts minerals from the Earth, and desalination removes salts from water; none of these processes converts organic waste into manure. Composting also diverts useful material from landfills.