Which of the following pollutants is biodegradable ?

Sewage is a pollutant that is biodegradable. Biodegradable means that the substance can be broken down naturally by microorganisms into simpler substances, such as water and carbon dioxide. Sewage contains organic matter that can be easily decomposed by bacteria, which is why it is considered biodegradable. This is also why wastewater treatment plants use bacteria to break down organic matter in sewage before releasing it into the environment. Plastics, metal scrap, lead compounds, and hydrogen sulfide are not biodegradable pollutants. Plastics can take hundreds of years to decompose, and even then, they only break down into smaller plastic particles that can cause harm to the environment and wildlife. Metal scrap and lead compounds do not break down naturally and can accumulate in the environment over time, leading to toxicity issues. Hydrogen sulfide is a gas that can be toxic to living organisms, but it does not biodegrade as it is a simple molecule that does not contain carbon.