Skip to content

We do not clean ponds or… (Class 10 Science 2023, Q26)

questionbuddy.in/q/cbse-10-science-2023-31-2-1-q26-not-clean-ponds-lakes-but

ScienceCBSE Class 10 · Board exam 2023, set 31/2/1 · 2 marks · Very short answer

CBSE Class 10 Science 2023: question 26

Set in the CBSE Class 10 board exam of 2023, paper 31/2/1, section B, question 26, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q26 · 2 marks · Very short answerCompetency-basedOur Environment

We do not clean ponds or lakes but an aquarium needs to be cleaned regularly. Why ?

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/2/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Which ecosystem is natural and which is artificial?

Hint 2

Which organisms break down dead matter and wastes in nature?

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. An aquarium is an artificial, man-made ecosystem. It does not have enough natural decomposers (bacteria and fungi) to break down dead remains and wastes. These wastes build up, so the aquarium must be cleaned regularly.

    1 mark

  2. Ponds and lakes are natural ecosystems. Decomposers in them break down dead organisms and wastes into simple substances that are recycled. These natural cleansing agents keep the water clean, so ponds and lakes need no cleaning.

    1 mark

Answer: An aquarium is an artificial ecosystem without natural decomposers; ponds and lakes are natural ecosystems where decomposers clean them.

Where the marks are

  • Aquarium is man-made and lacks decomposers or natural cleansing agents, so it needs cleaning (1 mark)
  • Ponds and lakes are natural ecosystems with decomposers that clean them (1 mark)

Revise the chapter

  • Chapter: Our Environment (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Our Environment, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 31/2/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.