CBSE Class 12-science Answered

Biodegradable wastes

Non-biodegradable wastes

1. These wastes can be broken down into non-poisonous substances by the action of microorganisms like bacteria and earthworms.

1. These wastes cannot be broken down into harmless substances by any biological processes.

2. Biodegradable substances change their form and structure over time and become harmless.

2. Non-biodegradable substances remain unchanged over a long period of time.

3. They do not pollute the environment.

3. Some of them remain inert and begin to accumulate in our surroundings, while others cannot be made less toxic easily and hence keep on polluting the environment.

Examples: Spoilt food, vegetable peels, tea leaves, wood, grass, paper, leather, cotton, cattle dung etc.

Examples: Glass bottles, metal cans, polythene bags, synthetic fibres, radioactive wastes, plastics and pesticides like DDT etc.