C
CraftExam
high importancemedium difficulty5 min

Biodegradable

Biodegradable substances are materials that can be broken down by microorganisms into simpler substances.

In one line: Bio means living, so living decomposers can break it down.

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Understand it

Microorganisms such as bacteria and fungi decompose biodegradable waste like vegetable peels, paper, and dry leaves. This makes such waste suitable for composting and natural recycling. The breakdown happens because living decomposers can act on the material over time.

Example

Vegetable peels thrown into a compost pit slowly change into compost with the help of microbes.

Rule to remember

Biodegradable = can be decomposed by microorganisms into simpler substances.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

  1. 1A paper napkin buried in moist soil gradually breaks down because microbes act on it.
  2. 2That is why paper is considered biodegradable.

Method you can reuse

  1. 1Ask whether microorganisms can break it down.
  2. 2Check if it decomposes naturally.
  3. 3If yes, classify it as biodegradable.
  4. 4Give a common example.

Sketch it in your answer

Show waste changing into compost through decomposers like bacteria and fungi.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

Why are vegetable peels called biodegradable waste?

Think first, then show answer
Vegetable peels are called biodegradable waste because bacteria and fungi can decompose them into simpler substances. They do not remain unchanged in the environment for a long time.

Common wrong answer

A common wrong answer is to call plastic biodegradable because it can become smaller pieces.

Why it loses marks: Microbes do not easily decompose plastic.

Don't mix this up

Students often think anything that breaks into small pieces is biodegradable. Breaking physically is not the same as being decomposed by microbes.

Exam tip

Link biodegradable waste with composting, soil enrichment, and decomposers in your answer.

Write it in the exam

Each point is worth about one mark. Write point 1 for a 1-mark question and keep adding points as the marks go up.

How CBSE asks it

Classify a material as biodegradable or non-biodegradable, or explain how composting works.
  1. 1

    Enough for 1 mark

    Biodegradable substances are materials that can be broken down by microorganisms into simpler substances.

  2. 2

    Add for 2 marks

    Example: Vegetable peels thrown into a compost pit slowly change into compost with the help of microbes.

  3. 3

    Add for 3 marks

    Microorganisms such as bacteria and fungi decompose biodegradable waste like vegetable peels, paper, and dry leaves.

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